Objectives -- After completing this module, you will be able to:

• Assess the implications of sampling decisions and procedures in terms of their impact on the confidence that someone can have in research results and conclusions (internal validity)
• Assess the implications of sampling decisions and procedures in terms of their impact on your ability to generalize research results statistically
• Assess the implications of sampling decisions and procedures in terms of their impact on your ability to general research results and conclusions theoretically
• Assess the implications of sampling decisions and procedures in terms of their impact on the explanatory power of a study
• Design sampling procedures that are adequate for your own research objectives, including conducting needs assessments and evaluating programs
  

Assigned Materials

Topic 1: Are all non-random, non-probability samples "bad" or can we use these samples to reach scientifically justifiable conclusions?

This is a pretty good discussion of non-probability sampling, but is far more critical of non-random sampling than I am. He does make it very easy to understand the differences between the types of non-random samples. If is very short. Non-Probability Sampling

Bernard, Chapter 7, pp. 162-177

Topic 2: So you've decided you will need a non-random, non-probability sample. What do you have to do to make sure it is "good enough" to reach generalizable conclusions?

Learning Guide to Non-Probability Sampling The learning guide for this week has specific sections for each of the three readings listed below. They are all important readings.

Malterud, K., Siersma, V.D. & Guassora, A.D. (2016) Sample size in qualitative interview studies: Guided by information power. Qualitative Health Research 26(13), 1753-1760. The best I have seen AND short. This is the primary reading for this week. Please read with care.

Topp, L., Barker, B. & Degenhardt, L. (2004) The external validity of results derived from ecstasy users recruited using purposive sampling strategies. Drug & Alcohol Dependence 73(1), 33-40. Read quickly. It's a pretty good example of purposive sampling. You do not need to be concerned with other aspects of the article -- focus on the sampling.

Auerswald, C., Greene, K., Minnis, A., Doherty, I. et al. (2004) Qualitative assessment of venues for purposive sampling of hard-to-reach youth: An illustration in a Latino community. Sexually Transmitted Diseases 31(2), 133-138. Read quickly for ideas on sampling -- the articles shows how to develop a sampling strategy, using more than one type of sample.

Topic 3: Does what we discussed last week still "count"?

Types of Samples (Random & Non-Random)

The Goals of Research Design

Additional Resources about Sampling This is a good week to share materials with your colleagues. This is a substantive list of materials about sampling that you can use to share ideas and earn some extra points!

Abrams, L.S. (2010) Sampling "hard to reach" populations in qualitative research. Qualitative Social Work 9(4), 536-550.

Alessi, M.G. & Miller, C.A. (2012) Comparing a convenience sample against a random sample of duck hunters. Human Dimensions of Wildlife 17(2), 155-158.

Barratt, M.J., Ferris, J.A. & Lenton, S. (2014) Hidden populations, online purposive sampling, and external validity: Taking off the blindfold. Field Methods 27(1), 3-21.

Benoot, C., Hannes, K. & Bilsen, J. (2016) The use of purposeful sampling in a qualitative evidence synthesis: A worked example on sexual adjustment to a cancer trajectory. BMC Medical Research Methodology 16, 1-12.

Bethlehem, J. (2016) Solving the nonresponse problem with sample matching. Social Science Computer Review 34(1), 59-77.

Bryant, J. (2014) Using respondent-driven sampling with "hard to reach" marginalised young people: Problems with slow recruitment and small network size. International Journal of Social Research Methodology 17(6), 599-611.

Chen, Y., Li, P., Wu, C. (2019) Doubly robust inference with nonprobability survey samples. J American Statistical Association 115(532), 2011-2021. DOI 10.1080/01621459.2019.1677241

Dutwin, D. & Buskirk, T.D. (2017) Apples to oranges or gala versus golden delicios? Comparing data quality of nonprobability internet samples to low response rate probability samples. Public Opinion Quarterly 81(special issue):213-249. DOI: 10.1093/poq/nfw061

Ellard-Gray, A., Jeffrey, N.K., Choubak, M. & Crann, S.E. (2015) Finding the hidden participant: Solutions for recruiting hidden, hard-to-reach, and vulnerable populations. International Journal of Qualitative Methods 14(5), 1-10.

Gile, K.J. & Handcock, M.S. (2010) Respondent-driven sampling: An assessment of current methodology. Sociological Methodology 40(1):, 285-327.

Griffith, D.A., Morris, E.S. & Thakar, V. (2016) Spatial autocorrelation and qualitative sampling: The case of snowball type sampling designs. Annals of the American Association of Geographers 106(4), 773-787.

Guest, G., Namey, E., McKenna, K. (2017) How many focus groups are enough? Building an evidence base for nonprobability sample sizes. Field Methods 29(1):3-22. DOI: 10.1177/1525822X16639015

Link, M. (2018) New data strategies: Nonprobability sampling, mobile, big data. Quality Assurance in Education 26(2):303-314. DOI DOI:10.1108/QAE-06-2017-0029

Mercer, A.W., Kreuter, F., Keeter, S. & Stuart, E.A. (2017) Theory and pratice in nonprobability surveys: Parallels between causal inference and survery inference. Public Opinion Quarterly 81(supplement):250-271. DOI: 10.1093/poq/nfw060.

Mookherji, S. & LaFond, A. (2013) Strategies to maximize generalization from multiple case studies: Lessons from the Africa Routine Immunization System Essentials (ARISE) project. Evaluation 19(3), 284-303.>

Rafail, P. (2017) Nonprobability sampling and Twitter: Strategies for semibounded and bounded populations. Social Science Computer Review 36(2):195-211. DOI: 10.1177/0894439317709431

Roy, K., Zvonkovic, A., Goldberg, A., Sharp, E. & LaRossa, R. (2015) Sampling richness and qualitative integrity: Challenges for research with families. Journal of Marriage and Family 77(1), 243-260.>

Simmons, A.D. & Bobo, L.D. (2015) Can non-full-probability internet surveys yield useful data? A comparison with full-probability face-to-face surveys in the domain of race and social inequality attitudes. Sociological Methodology 45(1), 357-387.

Sydor, A. (2013) Conducting research into hidden or hard-to-reach populations. Nurse Researcher 20(3), 33-37.

Yin, R.K. (2013) Validity and generalization in future case study evaluations. Evaluation 19(3), 321-332.