Convenience sampling is a non-probability sampling technique where subjects are selected because of their convenient accessibility and proximity to the researcher.The subjects are selected just because they are easiest to recruit for the study and the researcher did not consider selecting subjects that are representative of the entire population.In all forms of research, it would be ideal to test the entire population, but in most cases, the population is just too large that it is impossible to include every individual. This is the reason why most researchers rely on sampling techniques like convenience sampling, the most common of all sampling techniques. Many researchers prefer this sampling technique because it is fast, inexpensive, easy and thesubjectsare readily available.ExamplesOne of the most common examples of convenience sampling is using student volunteers as subjects for the research. Another example is using subjects that are selected from a clinic, a class or an institution that is easily accessible to the researcher. A more concrete example is choosing five people from a class or choosing the first five names from the list of patients.In these examples, the researcher inadvertently excludes a great proportion of the population. A convenience sample is either a collection of subjects that are accessible or a self selection of individuals willing to participate which is exemplified by your volunteers.UsesResearchers use convenience sampling not just because it is easy to use, but because it also has other research advantages.Inpilot studies, convenience sample is usually used because it allows the researcher to obtain basic data and trends regarding his study without the complications of using arandomized sample.This sampling technique is also useful in documenting that a particular quality of a substance or phenomenon occurs within a given sample. Such studies are also very useful for detecting relationships among different phenomena.CriticismsThe most obvious criticism about convenience sampling is sampling bias and that the sample is not representative of the entire population. This may be the biggest disadvantage when using a convenience sample because it leads to more problems and criticisms.Systematic biasstems from sampling bias. This refers to a constant difference between theresultsfrom the sample and the theoretical results from the entire population. It is not rare that the results from a study that uses a convenience sample differ significantly with the results from the entire population. A consequence of having systematic bias is obtaining skewed results.Another significant criticism about using a convenience sample is the limitation ingeneralizationand inference making about the entire population. Since the sample is not representative of the population, the results of the study cannot speak for the entire population. This results to a lowexternal validityof the study.NotesWhen using convenience sampling, it is necessary to describe how your sample would differ from an ideal sample that was randomly selected. It is also necessary to describe the individuals who might be left out during the selection process or the individuals who are overrepresented in the sample.In connection to this, it is better if you can describe the possible effects of the people who were left out or the subjects that are overrepresented to your results. This will allow the readers of your research to get a good grasp of the sample that you weretesting. It will also enable them to estimate the possible difference between your results and the results from the entire population.A purposive sample, also commonly called a judgmental sample, is one that is selected based on the knowledge of a population and the purpose of the study. The subjects are selected because of some characteristic.Field researchers are often interested in studying extreme or deviant cases that is, cases that dont fit into regular patterns of attitudes and behaviors. By studying the deviant cases, researchers can often gain a better understanding of the more regular patterns of behavior. This is where purposive sampling often takes place. For instance, if a researcher is interested in learning more about students at the top of their class, he or she is going to sample those students who fall into the "top of the class" category. They will be purposively selected because they meet a certain characteristic.Purposive sampling can be very useful for situations where you need to reach a targeted sample quickly and where sampling for proportionality is not the main concern.ExamplesIf a researcher is studying the nature of school spirit as exhibited at a school pep rally, he or she might interview people who did not appear to be caught up in the emotions of the crowd or students who did not attend the rally at all. In this case, the researcher is using a purposive sample because those being interviewed fit a specific purpose or description.Researchers (typicallymarket researchers) who you might often see at a mall carrying a clipboard and stopping various people to interview are oftenconducting researchusing purposive sampling. They may be looking for and stopping only those people who meet certain characteristics. For instance, if they are interested in the opinions of Hispanic females between 20 and 30 years old, they would stop the people passing by who look like they fit this description. One of the first things the researcher will do in this situation is verify that the respondent does in fact meet the characteristics or criteria for being included in the sample. If they do, the researcher will ask them the rest of the survey questions. If they do not meet the criteria, the researcher will likely send them on their way.

A quota sample a type ofnon-probability samplein which the researcher selects people according to some fixed quota. That is, units are selected into a sample on the basis of pre-specified characteristics so that the total sample has the same distribution of characteristics assumed to exist in the population being studied. For example, if you are a researcher conducting a national quota sample, you might need to know what proportion of the population is male and what proportion is female as well as what proportions of each gender fall into different age categories, race or ethnic categories, educational categories, etc. The researcher would then collect a sample with the same proportions as the national population.Meaning of dataData can be defined as a collection of facts, figures or any other related material, which has the ability to serve as the information for the basic study and the analysis. It must be kept in mind that data can be either old in nature or it may be the current one.For getting answers to any of the queries that are made data related to the questions or the queries is very much needed. Data acts as the back bone for the analysis, so it can be said that no question can be answered without the data.Analyzation of the data often leads to some of the inferences which are very commonly called as the information. The inference which is based on the guess work or on the opinions can never ever make a place in the research but the factors which play a critical role in the research generally include accuracy, suitability, reliability etc.Sources of dataThe basic data has a direct affect on the answers to the various questions and hence the source of the data is very much important as it provides the necessary information. The various sources of the data can be summarized as follows 1. Primary sources These types of the sources refer to the first hand sources or the original sources at the hands of a researcher, which is not collected in the past. Collection of the primary data can be done with the help of the principle sources of the observation and also the surveys. Primary data in very simple and general language can be defined as the first hand information relating to any type of the research that has been gathered or collected by the researcher or by any of his assistant or an agent.This type of the data helps in the original investigations and observations, which automatically further leads to the achievement of the various useful and meaningful results. A very important point to be kept in mind about these types of results obtained, which are based on the primary data are bound to be empirical in nature and also play a very critical and defining role in the research methodology.If the primary data that has been collected and compiled is not bias in the nature acts as a tool of great utility value as then this type of the data becomes very much reliable, accurate and dependable in nature that ultimately helps a great deal in carrying out the various specified investigations.Once this primary data is used the original features or the characteristics of these data diminish resulting in the formation of the secondary data.Hence it can be said that the data which acts as primary data at one point of time is bound to become secondary data at some stage or time in the future.Methods of the collection of the primary data can be categorized as a. Observation In general terms observation can be defined as the process involving the collection of the data by either viewing or listening or both. The best method in this category is to directly and personally observe something to get meaningful data this method is also called as the Direct Personal Observation. In this type of the observation the situation is observed by the researcher in order to collect data relevant to the research. If the observation is without any bias the data that is collected with the help of this type of method acts as the most reliable information.Observation is also a very cheap method and then also is very effective in its nature of working this method is a very old one data collected in the past about the human race, the environment etc used this method only.But a major drawback of this type of method is that with the help of observation one is not able to quantify the data and also one cannot reach to some concrete solutions on the basis of the data collected by this method. So it can be said that observation method should generally be used for carrying out hypothesis testing.b. Questionnaire and Schedule With the help of this type of method, data is collected by getting questionnaires completed by the various respondents. This method of questionnaire and schedule is generally employed in order to collect the primary data in a very systematic manner. A questionnaire can be defined as a schedule having a number of coherent questions related to the topic which is being studied. A questionnaire acts as a formulated series of the questions and helps in the collection of the information directly by the investigator himself. A schedule can be defined as the collection of the details in a tabulated form and can be sometimes identical to the questionnaire.2. Secondary sources Data can be referred to be secondary in nature if the information provided by the data is not related to the purpose of the research project work i.e. secondary data accounts to the information for the various other purposes and not the purpose involved in the given research work. Secondary data is readily available and the researcher himself has no control over the shape of the data as it is given shape by the others. This type of data is based on the second hand information i.e. the data that has been collected, compiled and presented in the past by some other company or group and is now being used in the various investigation procedures, this type of data is referred to as the secondary data.6.3.3 InterviewsIn interviews information is obtained through inquiry and recorded by enumerators. Structured interviews are performed by using survey forms, whereas open interviews are notes taken while talking with respondents. The notes are subsequently structured (interpreted) for further analysis. Open-ended interviews, which need to be interpreted and analysed even during the interview, have to be carried out by well-trained observers and/or enumerators.As in preparing a questionnaire, it is important to pilot test forms designed for the interviews. The best attempt to clarify and focus by the designer cannot anticipate all possible respondent interpretations. A small-scale test prior to actual use for data collection will assure better data and avoid wasting time and money.Although structured interviews can be used to obtain almost any information, as with questionnaires, information is based on personal opinion. Data on variables such as catch or effort are potentially subject to large errors, due to poor estimates or intentional errors of sensitive information.6.3.3.1 Open-ended interviewsOpen-ended interviews cover a variety of data-gathering activities, including a number of social science research methods.Focus groupsare small (5-15 individuals) and composed of representative members of a group whose beliefs, practises or opinions are sought. By asking initial questions and structuring the subsequent discussion, the facilitator/interviewer can obtain, for example, information on common gear use practices, responses to management regulations or opinions about fishing.Panel surveysinvolve the random selection of a small number of representative individuals from a group, who agree to be available over an extended period - often one to three years. During that period, they serve as a stratified random sample of people from whom data can be elicited on a variety of topics.6.3.3.2 Structured interviewGenerally, structured interviews are conducted with a well-designed form already established. Forms are filled in by researchers, instead of respondents, and in that it differs from questionnaires. While this approach is more expensive, more complicated questions can be asked and data can be validated as it is collected, improving data quality. Interviews can be undertaken with variety of data sources (fishers to consumers), and through alternative media, such as by telephone or in person.Structured interviews form the basis for much of the data collection in small-scale fisheries.In aninterview approach for sample catch, effort and prices,the enumerators work according to a schedule of landing site visits to record data. Enumerators can be mobile (that is sites are visited on a rotational basis) or resident at a specific sampling site. Their job is to sample vessels, obtaining data on landings, effort and prices from all boat/gear types that are expected to operate during the sampling day. The sample should be as representative as possible of fleet activities. Some additional data related to fishing operations may be required for certain types of fishing units, such as beach seines or boats making multiple fishing trips in one day. For these, the interview may cover planned activities as well as activities already completed.In aninterview approach for boat/gear activities,the enumerators work according to a schedule of homeport visits to record data on boat/gear activities. Enumerators can be mobile (that is homeports are visited on a rotational basis) or resident at a specific sampling site. In either case, their job is to determine the total number of fishing units (and if feasible, fishing gears) for all boat/gear types based at that homeport and number of those that have been fishing during the sampling day.There are several ways of recording boat/gear activities. In many cases, they combine the interview method with direct observations. Direct observations can be used to identify inactive fishing units by observing those that are moored or beached, and the total number of vessels based at the homeport are already known, perhaps from a frame survey or register. Often enumerators will still have to verify that vessels are fishing as opposed to other activities by using interviews during the visit.The pure interview approach can be used in those cases where a pre-determined sub-set of the fishing units has been selected. The enumerator's job is to trace all fishers on the list and, by means of interviewing, find out those that had been active during the sampling day. For sites involving a workable number of fishing units (e.g. not larger than 20), the interview may involve all fishing units.Sometimes it is possible to ask questions on fishing activity which refer to the previous day or even to two days back. This extra information increases the sample size significantly with little extra cost, ultimately resulting in better estimates of total fishing effort. Experience has shown that most of the variability in boat/gear activity is in time rather than space.6.3.4 Direct observations6.3.4.1 ObserversObservers can make direct measurements on the fishing vessels, at landing sites, processing plants, or in markets. The variables that enumerators can collect include catch (landing and discards), effort, vessel/gears, operations, environmental variables (e.g. sea state, temperature), biological variables (e.g. length, weight, age), the values and quantities of landings and sales.In practice, observers do not only make direct measurements (observations), but also conduct interviews and surveys using questionnaires. They might also be involved in data processing and analysis. The tasks of an observer are difficult and adequate training and supervision are therefore essential.Clear decisions need to be made on the nature and extent of data collected during any one trip. Often, the amount of data and frequency of collection can be established analytically with preliminary data.Preferably, observers should only collect data, not carry out other activities, such as enforcement, licensing or tax collection. This should help to minimise bias by reducing the incentives to lie. Problems in terms of conflicts between data collection and law enforcement, for example, can be reduced by clear demarcation, separating activities by location or time. This becomes a necessity for at-sea observers. Their positions on fishing vessels and the tasks that they perform depend significantly on a good working relationship with the captain and crew, which can be lost if they are perceived as enforcement personnel.The major data obtained throughat-sea observersare catch and effort data, which are often used for cross checking fishing logs. At the same time, the at-sea observers can collect extra biological (fish size, maturity, and sex), by-catch and environmental data, as well as other information on the gears, fishing operations etc. Frequently, discards data can only be collected by at-sea observers.The main data obtained fromobservers at landing sites, processing plants and marketsinclude landing (amount, quality, value and price), biological (size, maturity), and effort (how many hauls, hours fishing) data. For the large-scale fishery where a logbook system is used, data collected at landing sites could be used to crosscheck data recorded in logbooks. Data collected from processing plants include quantities by species and, especially in modern factory practices, the batch number of raw materials, which can sometimes be traced back to fishing vessels. These data if collected can be used to validate landing data.Collecting data to estimate raising factors for converting landed processed fish weight to the whole weight equivalent may be necessary. By sampling fish before and after processing, conversion factors may be improved. Potential seasonal, life history stage and other variations in body/gut weight ratios suggest date, species, sex and size should be recorded in samples.Economic and demographic data at each level (e.g. input and output of various products to and from market and processors) are usually obtained by interview and questionnaire. However, the data directly collected by enumerators can also be the major source as well as supporting data for those collected through other methods.While product data in processing plants can be collected through questionnaire (6.3.2) or interview (6.3.3), enumerators can directly collect many physical variables (weight, number, size etc.) more accurately. Automatic scales, through which a continuous stream of fish passes, can record the weight of fish mechanically or through computerised sensors. Similarly, mechanical or automatic weighing bins for whole frozen or defrosted fish, prior to entry to a processing line or cold store, can be used to record weights for each batch. Otherwise, boxes need to be counted and sub-sampled to ensure their fish contents are correctly identified and weighed.Fish is often landed in bulk together with non-fish materials (e.g. ice, brine slurry, packing material and pallets). It can be very difficult to estimate the total fish weight, let alone weight by species, product and size grade. Methods need to be established to record whether non-fish material is included in any weighing process (e.g. are scales set to automatically subtract pallet weight?). In the case of processed fish in sealed boxes, it may be that sampling to determine an average weight and then box or pallet counting is sufficient. Alternatively, each box or pallet is weighed and a note taken whether box and pallet weight should be subtracted at a later data when processing the data.Complete landings of all catch in relation to a vessel's trip (i.e. emptying of holds) is preferred since records can then be matched against logsheets. However, in some circumstances off-loading in harbours, at the dock or at sea may only be partial, some being retained on board until the next off-loading. In this case, records should be maintained of both catch landed and retained on board.6.3.4.2 InspectorsInspectors are a kind of enumerator involved in law enforcement and surveillance (for fishing regulations, sanitary inspections, labour control, etc.). They may work at sea on surveillance vessels, at landing sites on shore, at processing factories and at markets. In general, scientific data are better collected by enumerators who are not directly involved in law enforcement. Nevertheless, many variables collected by the inspectors are very useful, and include landings, operational information, effort, landing price, processing procedure and values of product to the market and processors. Inspectors are also useful in collecting employment data.Inspectors may play an important role in verification. In many cases, reports can be physically checked with observations. For example, random samples of boxes can be taken to check box contents (species, product type and size grade) against box identification marks. Inspectors need to be skilled in such sampling strategies.As with enumerators/observers, inspector data should be treated with caution because of the high chance of sampling bias. This potential bias of data collected by law-enforcement officers should be considered in analyses.6.3.4.3 Scientific researchEcological research methods can be undertaken independent of commercial fishing operations to measure variables related to fish populations or the environment. Such research can be carried out by institutional research vessels or by industry or institutions using commercial fishing vessels. The objective is to obtain observations on biological (e.g. stock abundance or spatial distribution and fish size, maturity and spawning activities) and environmental (e.g. salinity and temperature) variables. It is important that this type of research is carried out periodically in order to obtain time sequential data.Similarly, socio-cultural research methods can be used to obtain specific information useful to management. Although these methods may not often be considered routine, they provide important data and should be considered for infrequent data collection where possible.Key informantsare individuals with specialised knowledge on a particular topic. They may include academic specialists, community leaders, or especially skilled fishers. Interviews are usually begun with a set of baseline questions, but the interviewer expects to elicit new and perhaps unexpected information by requesting that the key informant expand on his or her answers to these initial questions. This method is ideal for obtaining in-depth descriptive data on beliefs and practices, including historical practices.Participant-observationis a technique whereby the researcher spends an extended period of time (from weeks to years, depending on the objective and the context) living with a target community, both observing their behaviour and participating in their practices. During this time, the researcher will be conducting formal and informal open-ended interviewing on a variety of topics. This is a good method for learning about the actual processes of decision-making, as opposed to the formal procedures. Cultural and institutional rules are rarely followed to the letter, and there are usually informal standards for an acceptable leeway. However, information on these standards can often only be obtained through participant-observation.6.3.4.4 Data loggingAutomatic Location Communicators (ALC) automatically log data through positioning and communications technology. They allow remote observation through recording of fishing activities at sea, and could replace logbooks and observers/inspectors on the bridges of fishing vessels. However, ALCs will be deficient in one simple respect: entry of data on the catch remains the responsibility of the captain.Many data on fishing operations can be automatically recorded from bridge instrumentation. Position, speed, heading, deployment of gear through links to electronic instruments are likely to become more common in future. Once gathered, such data may be automatically transmitted to databases through satellite or ground communications.The technology that combines vessel position and a catch assessment for management authorities through remote means is generally known as a Vessel Monitoring System (VMS). Confidentiality is the key to the widespread acceptance of VMS, as information on current fishing grounds, and therefore security of position information, is a major concern.However, vessel positions, activities and catch reporting through these systems, directly to databases and thence to reports that either aggregate data or remove vessel identifiers are becoming possible. Since it will be relatively simple to check remotely sensed position against recorded position, logsheet records should become more representative of real vessel activities at sea.6.3.5 ReportingIn most complete enumeration approaches, fisheries staff do not directly undertake data collection, but use external data sources. Most commonly, these sources are data forms completed by the fishing companies themselves, middle persons, market operators, processors and even trading companies and custom offices. Such methods are almost exclusively used for semi-industrial and industrial fisheries and institutions.Fishing companies are often a good source of information regarding basic data on catches and fishing effort. Regular submission of basic data is a part of the fishing licensing process. Data submitted by companies are often in the form of logbooks or landings declarations. Logbooks should contain detailed information on individual fishing operations, including fishing grounds, type and duration of operation, catch by species and other types of data relating to weather and sea conditions. Landings declarations usually deal with grouped data presented as summaries of fishing trips and catch by species.The advantage of using reports is that data are compiled by agents other than fisheries staff and sometimes can be made available in pre-processed computerised format directly from the company's records, thereby reducing administration costs. Confidentiality of information (such as fishing grounds and catch rates) should be part of the agreement for data submission, and statistical outputs of the survey should not contain information related to individual fishing vessels or companies. However, there are also risks of under-reporting or of deliberate distortion of data, especially fishing ground, catch and revenue related information.6.3.5.1 HarvestThe collection of data from all vessels within a fishery sector is sometimes needed usually from large-scale fisheries. Normally each vessel will be required to record their catch and effort data for every trip on a specially designed logbook. Because it is a painstaking task, usually only essential data are required. For various reasons, the data collected by this method could be inaccurate and thus validation from time to time by inspectors is important.6.3.5.2 Post harvestData from post harvest operations are often used for obtaining information on landings, biology, markets, costs and earnings. Where logsheets, landings records and market reports are not available, reliable information can often only be obtained from processing factories. Reports by the processors generally include quantities and value of fish received and the resulting products. Additional information may include the origin of catch (fishing and transport vessels) and size categories of fish.Monitoring off-loading catch in processed or whole round form requires considerable attention to detail and much depends on the relationship between the fishery authority and vessel captains or companies. It may be that sufficient trust has been developed to allow vessel or company off-loading records to be used directly, perhaps with random spot checks.In some circumstances, off-loading may proceed directly to a processing factory or cold store (particularly by conveyor of bulk fish such as small pelagics, tuna etc.). Detailed landings can still be recorded as long as each batch is marked with its source (vessel name and trip identifier).Most factories will maintain records of fish (by species, product type and size grade) that enter processing directly or cold store. They will also maintain information on their output and sales, including destination and price, although such data may be much more difficult or impossible to obtain unless legally required. Data forms will need to be customised to the type of processing and the factory management system.6.3.5.3 SaleMarket transaction records may form a feasible way of collecting landings with complete enumeration, particularly in large fleets of small-scale vessels that land in central locations. All invoices, sales slips or sales tallies should be designed with care as to content, style and availability to ensure completeness of coverage. Given the potential volume of paper work, simplicity and brevity will often be the most important criteria.The primary identifier on records should be the name of the vessel (including all carrier vessels unloading from more distant fleets) that sold the catch, and the date or trip number, since vessels may make more than one sale from one landing. Total weight by species or commercial group, and price should be collected. Ideally, further data should be obtained on fishing ground and level of fishing effort, although often this is not possible.In similar fashion to logsheets and landings sheets, sales records should be prepared in appropriately identified forms in multiple copies as required. Copies are likely to be required for the market administration (if necessary), the seller, the buyer and the fishery authority.General sales records, such as volume of sales and prices by product type, provide useful information for bio-economic analyses and a source of data on catch and landings when all other avenues for data collection are unavailable. Three information sources on general sales are usually available: market, processing factory and export data. However, these data must always be treated with care. The further away the data sources are from the primary source, the more errors will be introduced, and the more details (e.g. fishing ground, fishing effort) will be lost.In addition to these, direct surveys of fishing companies may provide vital details upon which overall fisheries management and administration can be based. Annual fisheries statistical surveys can be voluntary or compulsory. If voluntary, responses will depend on the level of co-operation between the private sector and the authorities. If compulsory, legislation is required and can be drafted in various forms, such as Companies or Statistics Acts.6.3.5.4 TradeTrade data refers to information from customs or similar sources on trade. These data are used in socio-economic indicators and, in some exceptional cases, support landings data.Information on exports and imports is published in most countries. It is particularly important where export or import taxes are payable, or export incentives given. Of course, export and import data is of limited use in estimating the total production of fish unless there are also means to establish the proportion of catch that is used in domestic consumption. However, in some particular cases, the trade data are the main source for estimating landings (e.g. shark, tunas). If trade data are used for validating or estimating landings, the quantities will usually need converting to whole weight.The lack of detail in export data can be a problem simply because of the form in which they are collected. Export categories recorded by the authorities (not usually in co-operation with fishery authorities) can mask much of the information required. Canned fish, frozen fish, fresh fish, dried fish and fishmeal may be the only relevant categories for export authorities. Together with accurate raising factors, these data can be used for total fish production. This method of estimation is fairly accurate when there is a small local market. However, unless they are broken down by species and linked back directly to sources of data closer to the harvest sector, they provide little value for fishery management purposes. .Data can be divided into two types, namely quantitative and qualitative. Quantitative data is numerical in nature and can be mathematically computed . Quantitative data measure uses different scales, which can be classified as nominal scale, ordinal scale, interval scale and ratio scale. Nominal scale is used to categorize items into different group, for example male and female, different examination grades, different races in a country, different types of companies, different shoe sizes and so on. The statistics that is used to analyze this type of data is mode. The second measure for quantitative data is the ordinal scale which other than providing information as the nominal scale does also permit ranking of the data. For example, shoe sizes can be ranked from big to small. A typical ordinal in ranking a set of data is poor, satisfactory, good, very god, excellent. On the other hand, an interval scale not only rank order of a set of data, it also measure the order in units of equal intervals. However, the starting point for the measurement is arbitrary rather than absolute. For example, Celsius in temperature measurement is an interval scale because 0oC is an arbitrary value, it is not absolute zero, it does not mean temperature is lacking at that point. For absolute quantities, we have to use the ratio scale. For example, measuring temperature in Kelvin is a ratio scale as it starts the measurement at absolute zero, which is about -273oCelsius.Qualitative data are mostly non-numerical and usually descriptive or nominal in nature. This means the data collected are in the form of words and sentences. Qualitative methods are ways of collecting data which are concerned with describing meaning, rather than with drawing statistical inferences.What qualitative methods (e.g. case studies and interviews) lose on reliability they gain in terms of validity.They provide a more in depth and rich description

COLLECTION OF DATA THROUGH SCHEDULESThis method of data collection is very much like the collection of data through questionnaire, with little difference which lies in the fact that schedules (proforma containing a set of questions) are being filled in by the enumerators who are specially appointed for the purpose. These enumerators along with schedules, go to respondents, put to them the questions from the proforma in the order the questions are listed and record the replies in the space meant for the same in the proforma. In certain situations, schedules may be handed over to respondents and enumerators may help them in recording their answers to various questions in the said schedules. Enumerators explain the aims and objects of the investigation and also remove the difficulties which any respondent may feel in understanding the implications of a particular question or the definition or concept of difficult terms.This method requires the selection of enumerators for filling up schedules or assisting respondents to fill up schedules and as such enumerators should be very carefully selected. The enumerators should be trained to perform their job well and the nature and scope of the investigation should be explained to them thoroughly so that they may well understand the implications of different questions put in the schedule. Enumerators should be intelligent and must possess the capacity of cross examination in order to find out the truth. Above all, they should be honest, sincere, hardworking and should have patience and perseverance.This method of data collection is very useful in extensive enquiries and can lead to fairly reliable results. It is, however, very expensive and is usually adopted in investigations conducted by governmental agencies or by some big organisations. Population census all over the world is conducted through this method.Schedule in Research MethodologyA schedule is a structure of set of questions on a given topic which are asked by the interviewer or investigator personally. The order of questions, the language of the questions and the arrangement of parts of the schedule are not changed. However, the investigator can explain the questions if the respondent faces any difficulty. It contains direct questions as well as questions in tabular form.Schedule include open-ended questions and close-ended questions. Open-ended questions allow the respondent considerable freedom in answering. However, questions are answered in details. Close-ended questions has to be answered by the respondent by choosing an answer from the set of answers given under a question just by ticking.Following are the different types of schedules used by social scientists and anthropologists. Village or community schedule:It is used by census researchers who collect general information on populations, occupations, etc. Family or Household schedule:It gives full demographic details of households, the status of individuals, data on education, age, family relations etc. Opinion or attitude schedule:To schedule the views of population regarding an issue.Questionnaire in Research MethodologyA questionnaire refers to a device for securing answers to questions by using a form which the respondent fills in by himself. It consists of a number of questions printed or typed in a definite order. These forms are actually mailed to the respondent who was expected to read and understand the questions and reply to them by writing the relevant answers in the spaces provided. Ideally speaking respondent must answer to a verbal stimulus and give a written or verbal response. It is totally devoid of any table. Its purpose is to collect information from the respondents who are scattered over a vast area.Questionnaire include open-ended questions and close-ended questions. Open-ended questions allow the respondent considerable freedom in answering. However, questions are answered in details. Close-ended questions has to be answered by the respondent by choosing an answer from the set of answers given under a question just by ticking.Following are the different types of Questionnaire used by social scientists and anthropologists. Structured questionnaire:It include definite, concrete and pre-obtained questions which were prepared in advance. Closed-form questionnaire:It is used when categorized data is required. Pictorial questionnaire:It is used to promote interest in answering after seeing the pictures on a particular theme. Unstructured questionnaire:Designed to obtained view points, opinions, attitudes and to show relationships and inter-connections between data which might escape notice under more mechanical types of interrogations.A schedule however, takes more time as compared to a questionnaire. A questionnaire has less data collecting ability than a schedule. A questionnaire can cover a very wide field of data whereas a schedule is a problem oriented data collecting method. A questionnaire take for itself and is self-explanatory, whereas schedule has to be explained by the investigator. 1. Experiment - We actively impose treatment on some individuals in order to observe a response. If we choose individuals for treatment well, then we will be able to make a causal connection between treatment and response. All of these methods have the potential to generatebias- that is to measure something in the population incorrectly. Random bias - bias due to random chance - we will learn how to measure our uncertainty here Systematic bias - bias due to technique of data collection or measurementExperimentDivide subjectsrandomlyinto at least one treatment group (factors) and a control groupTreatment group(s) receive treatmentControl group receives no treatment (problem of the placebo effect)Examine relationship between treatment and control group for some response variable (aspirin -> heart attack).Experiments provide good evidence for causation because treatment is completely randomly assigned and thus there are no lurking variables.Relationship still might be due to random chance, but as we will learn we can measure the likelihood of this.Cautions Placebo Effect Double-blind Producing realistic contexts (particularly a problem in social science research)More common in the social sciences are so-called"natural experiments."A natural experiment is a situation in which through some outside shock to a social system, a treatment effect is delivered which cannot be the cause of lurking variables. (example: Mariel boat lift)Survey Sampling DesignDesigned ExperimentsThere are two basic methods for experiments:Anobservational studyobserves individuals and measures variables of interest but does not attempt to influence the responsesAdesigned experimentdeliberately imposes some treatment on individuals in order to observe their responsesExamplesay we want to test two different diets for their effectiveness in losing weight. We advertise in the newspaper and on a certain day people who want to participate come to our office. ThereA) we have two tables. On each there is an explanation of one of the diets and a sign-up sheet. Our participants can read the material and eventually sign up for one of the two diets observational studyB) when a participant comes in we have him/her flip a coin. If it comes up headsthe person does diet 1, otherwise diet 2 designed experimentWhich of the two methods is better, and why?The individuals on which an experiment is done are calledexperimental units. When the units are humans they are calledsubjects. A specific experimental condition applied to a unit is called atreatment.It can be presumed that in such an inquiry,when all items are covered, no element of chance is left and highest accuracy is obtained. But inpractice this may not be true. Even the slightest element of bias in such an inquiry will get larger andlarger as the number of observation increases. Moreover, there is no way of checking the element ofbias or its extent except through a resurvey or use of sample checks. Besides, this type of inquiryinvolves a great deal of time, money and energy. Therefore, when the field of inquiry is large, thismethod becomes difficult to adopt because of the resources involved. At times, this method is practicallybeyond the reach of ordinary researchers. Perhaps, government is the only institution which can getthe complete enumeration carried out. Even the government adopts this in very rare cases such aspopulation census conducted once in a decade.