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Activity 3.5: Probability Sampling Plans
Background: It might be best to structure your research study around probability sampling if you suspect that the type of research question you’re asking would result in different kinds of answers, trends, or experiences depending on your participants’ key individual attributes. Probability sampling is also most commonly used in complex, large, diverse social groups in which subgroup members’ lifeways, experiences, behaviors, and ideas are likely to substantially differ.
This activity will help you decide on and justify optimal probability sampling plans based on case studies.
Key Terms and Concepts
Probability sample
Simple random sample
Stratified random sample
Disproportionate sampling
Cluster sample
Instructions
Using the case study prompts, make decisions regarding optimal probability sampling plans (simple random vs. stratified random vs. cluster) and justify your decisions.
Common Mistakes
Common mistakes students make when choosing a probability sample plan:
Insufficient attention to the details of the research question
Insufficient attention to the details of the participants needed
Insufficient attention to the details of the researcher’s limitations
Ask Yourself
Am I monitoring my understanding? Have I backed up to reread a section to better understand content?
Sample Problem
A graduate student is working with a faculty research team to understand how people’s strategies for avoiding health effects from extreme heat (such as heat stroke) in a highly urbanized location differ based on neighborhood.
Example
Optimal sampling plan: Cluster
Justification: Because the researchers anticipate different strategies based on neighborhood location in a bigger urban area, each neighborhood will need its own sample. It might be best to recruit people from key neighborhood locations where lots of different people will go, such as convenience or grocery stores, so that even homeless people are included (because they’re likely to be most affected by extreme heat).
Non-example
Optimal sampling plan: Stratified random
Justification: Every neighborhood in the study has to be sampled, because the researchers want to know differences between neighborhoods.
Problem 1
A student is doing a senior thesis on how people’s own religious ideas are impacted by conversations with and proximity to people of other religions. The student selected New York City as the field site, because it is highly diverse. The student’s research is an exploratory study. They plan to follow up with interviews in different religious communities as a graduate student.
Optimal sampling plan:
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Justification:
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Problem 2
A graduate student is studying parenting styles and relationships between co-parents (roles, responsibilities, and expectations) in the United States, trying to understand if there are certain trends based on urban versus rural families.
Optimal sampling plan:
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Justification:
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Activity 3.6: Sampling Frames
Background: A sampling frame is a list of units of analysis from which you’ll take the sample and to which you’ll generalize. Popular sampling frames include telephone directories (though this has become more difficult in the era of mobile phones), tax rolls, or even a community census you produce yourself (which is especially helpful in areas in which the total population is not too large but lacks a readily available sampling frame).
This activity will help you select a sampling frame and identify participants you may be excluding as a result (i.e., identify the sampling frame’s limitations).
Key Terms and Concepts
Probability sample
Sampling frame
Instructions
For each of the prompts, brainstorm individually or in small groups to identify two potential sampling frames for recruiting participants for your probability sample. For each of the potential sampling frames, in the Sampling Frame Graphic Organizer (at the end of the chapter), identify potential problems and limitations (including which participants may be excluded from it). Then select which sampling frame you will use and justify your decision, as well as plan ways to alleviate the limitations when possible.
Common Mistakes
Common mistakes students make when selecting sampling frames:
Failing to be creative about how they might gain participants and alleviate limitations
Failing to adequately explore how their sampling frame may exclude certain participants
Ask Yourself
Am I monitoring my understanding? Have I backed up to reread a section to better understand content?
Sample Problem
A graduate student is working with a faculty research team to understand how people’s strategies for avoiding