Sampling Techniques & Participant Recruitment Flashcards

A market research firm needs 100 completed interviews and assigns interviewers to recruit specific numbers of men and women in each age bracket. This describes:

Answer: Quota sampling

Quota sampling sets predetermined targets for subgroup representation and allows interviewers to recruit non-randomly until quotas are filled.

When calculating the minimum sample size, increasing the desired confidence level from 90% to 95% will:

Answer: Increase the required sample size

A higher confidence level requires a larger critical value (z-score), which increases the calculated minimum sample size needed to achieve that confidence.

In a multistage sampling design, which sequence correctly describes the process?

Answer: Select clusters, then subgroups, then individuals

Multistage sampling progressively narrows selection from larger units (e.g., counties) to intermediate units (e.g., schools) to final units (e.g., students).

Which participant recruitment method poses the greatest risk of self-selection bias?

Answer: Opt-in online surveys

Opt-in online surveys attract only those who choose to participate, systematically overrepresenting people with strong opinions or high interest in the topic.

A design effect (DEFF) greater than 1.0 in cluster sampling indicates:

Answer: The variance is larger than under simple random sampling

A DEFF > 1.0 means that clustering increases variance compared to SRS, requiring a larger sample to achieve the same precision.

Which IRB requirement is most directly related to participant recruitment practices?

Answer: Obtaining informed consent before participation

IRBs require researchers to obtain voluntary informed consent from participants before collecting data, ensuring ethical recruitment practices.

Address-based sampling (ABS) is considered an improvement over random digit dialing (RDD) primarily because:

Answer: It provides broader coverage including cell-only households

ABS uses postal address files which cover nearly all households including those with only cell phones, reducing the undercoverage that affects RDD frames limited to landlines.