Chapter 6 - StandardizedMeasurement and

Assessment

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What is measurement?

• the act of measuring• assigning symbols or numbers to

something according to a specific set ofrules

What are the four differentlevels or scales ofmeasurement?

•Nominal Scale

•Ordinal Scale

•Interval Scale

•Ratio Scale

What is essential to knowabout the Nominal Scale?

• it’s the simplest form of measurement• it uses symbols, such as words or

numbers• it measures categorical variables

LABELIDENTIFY

CLASSIFY

What is essential to knowabout the Ordinal Scale?

• it’s a rank-order scale• it doesn’t indicate how much greater

one ranking is over another

What is essential to knowabout the Interval Scale?

• it’s also a rank-order scale• includes equal distances

or intervals betweenadjacent numbers

• the absence of a zeropoints means you cannotmake “ratio statements”

What is essential to knowabout the Ratio Scale?

• it’s the highest level of quantitativemeasure

• it has all the properties of the nominal,ordinal, and interval scales plus it has atrue zero point

• it is not often used in educationalresearch

Nominal

-labels things-

Ordinal

-ranks things-

Interval

-ranks w/ equal distances

Ratio

-ranks & labels-

Scales of Measurement

How do we define testing?

• the measurement of variables

How do we define assessment?

• gathering data to make evaluations

How do we define error?

• the difference between true scores andobserved scores

How do we define traits?

• distinguishable, enduring ways in whichone individual differs from another

How do we define states?

• distinguishable but less enduring waysin which individuals vary

What are the twelve assumptionsunderlying testing andmeasurement?

psychologicaltraits & states

exist

psychological traits & states

can be measured

various approachesto measurement

can be useful

assessments can answer

some of life’s most important

questions

What are the twelve assumptionsunderlying testing andmeasurement?assessment can pinpoint phenomena that require further study

various sourcesof data

enrich & are partof the assessment

process

various sourcesof error

are alwayspart of the assessment

process

measurementtechniques

have strengths&

weaknesses

What are the twelve assumptionsunderlying testing andmeasurement?test-related

behaviorpredicts non-test

relatedbehavior

testing &

assessmentcan be done in a fair

and unbiasedway

present-day samplingpredicts

future behavior

testing &

assessmentbenefitsociety

What is the difference betweenreliability and validity?

• Reliability refers tothe consistency of ascore

• Validity refers to theaccuracy of theinterpretations youmake from the scores

If you want validity, you must have reliability.

What is a reliability coefficient?

• a correlation coefficient that is used as anindex of reliability

• Researchers want reliability coefficients to beas close to +1.00 as possible

What are four different ways ofassessing reliability?

1. Test-Retest Reliability2. Equivalent Forms Reliability3. Internal Consistency Reliability4. Interscorer Reliability

What is test-retest reliability?

• a measure of the consistency of scores overtime

• the time interval can have an effect on test-retest reliability because people change overtime

What is equivalent forms reliability?

• the consistency of a group of individuals’scores on two equivalent forms of a testmeasuring the same thing

• the success of this method depends on theability to construct two equivalent forms of thesame test

What is internal consistencyreliability?

• the consistency with which the items on a testmeasure a single construct

What is are two indexes of internalconsistency?

• split-half reliability: splitting a test into twoequivalent haves and then assessing theconsistency of the scores across the twohalves of the test

• each ha

What is split-half reliability?

• splitting a test into two equivalent halves andthen assessing the consistency of the scoresacross the two halves of the test

• each half needs to be equal to the other informat, style, content, and other aspects

What is coefficient alpha?

• a formula that provides an estimate of the reliabilityof a homogeneous test or an estimate of thereliability of each dimension in a multidimensionaltest

• tells you the degree to which the items areinterrelated

• need to consider the number of items; don’t justassume that because the coefficient alpha is large,the items are strongly related

What is interscorer reliability?

• the degree of agreement or consistencybetween two or more scorers, judges, orraters

• some degree of training and practice for thescorers is advised to improve the reliability ofan evaluation

What is the definition of validity?

• the accuracy of the inferences, interpretations, oractions made on the basis of test scores

• to make sure that our test is measuring what weintended it to measure for the particular people in aparticular context and that the interpretations wemake on the basis of the test scores are correct

• we want our inferences to be accurate and aouractions to be appropriate

What is the definition of validityevidence?

• the empirical evidence and theoreticalrationales that support the inferences orinterpretations made from the test scores

What is the definition of validation?

• the process of gather evidence that supportsinferences made on the basis of test scores

• the best rule is to collect multiple sources ofevidence