Planning an Applied Research Project

Chapter 8 – Sampling Issues in Research

© 2014 John Wiley & Sons, Inc. All rights reserved.

Learning Objectives» Explain the reasons for sampling

» Distinguish between probability and non-probability sampling methods

» Select an appropriate sampling procedure

» Explain the types of sampling bias

» Avoid sampling bias in your research designs now and in the future

© 2014 John Wiley & Sons, Inc. All rights reserved.

Key Terms» Acquiescence bias» Analytic process errors» Area sampling» Auspices bias» Cluster sampling» Confidence level»  Convenience sampling»  Destructive sampling» Double sampling» Extremity bias

» Intercept sampling» Inference errors» Internet sampling» Interpretation errors» Interviewer interaction

bias» Judgmental sampling» Moderating variables» Non–probability

sampling» Non-response bias» Quota sampling

© 2014 John Wiley & Sons, Inc. All rights reserved.

Key Terms(cont’d)˃ Precision˃ Probability sampling˃ Purposive sampling˃ Proportional stratified

sampling˃ Recording error˃ Relevant sample˃ Respondent bias˃ Sample frame˃ Sample selection

process˃ Sample size

» Simple random sampling

» Snowball sampling» Social desirability bias» Stratified random

sampling» Systemic bias» Systemic bias errors» Target sample

© 2014 John Wiley & Sons, Inc. All rights reserved.

Reasons for SamplingS Staff

T Time

E Efficiency

A Accuracy

M Money or Resources

© 2014 John Wiley & Sons, Inc. All rights reserved.

Strategies for Selecting a Sample» Probability sampling

» Non-probability sampling

» Internet sampling

© 2014 John Wiley & Sons, Inc. All rights reserved.

Probability Sampling Strategies» Area sampling

» Custer sampling

» Double sampling

» Proportional stratified random sampling

» Simple random sampling

» Stratified random sampling

© 2014 John Wiley & Sons, Inc. All rights reserved.

Non-Probability Sampling Strategies» Convenience sampling

» Destructive sampling

» Intercept sampling

» Purposive or judgmental sampling

» Quota sampling

» Snowball sampling

© 2014 John Wiley & Sons, Inc. All rights reserved.

Sources of Sample Bias» Three Forms of Bias

˃ Systemic bias

˃ Respondent bias

˃ Interviewer bias

© 2014 John Wiley & Sons, Inc. All rights reserved.

Systemic Bias» Analytic process errors

» Moderating variables

» Systemic bias

© 2014 John Wiley & Sons, Inc. All rights reserved.

Respondent Bias» Acquiescence bias

» Auspices bias

» Extremity bias

» Non-response bias

» Social desirability bias

© 2014 John Wiley & Sons, Inc. All rights reserved.

Interviewer Bias» Inference errors

» Interviewer interaction bias

» Interpretation errors

» Recording errors

© 2014 John Wiley & Sons, Inc. All rights reserved.

Sample Size» Purpose of the research

» Level of confidence needed

» Extent of precision required or desired

© 2014 John Wiley & Sons, Inc. All rights reserved.

Review of Class Session» Anything unclear?

» One thing that I learned from this class is …

© 2014 John Wiley & Sons, Inc. All rights reserved.