Why is a large refusal rate a barrier to widespread generalization? (Select all that apply.)

Question

a. If a study has a refusal rate higher than thirty percent, it is no longer considered research.
b. If researchers cannot recruit subjects into their research studies, their credibility and ethics are under serious scrutiny.
c. The actual sample is not representative of the population. It is representative only of the elements of the population that chose to participate.
d. If many persons refuse to participate, they might refuse to participate in interventions that the study recommends.

Answer 1

ANS: A, B, C
Sampling theory was developed to determine mathematically the most effective way to acquire a sample that would accurately reflect the population under study. For a sample to be representative, it must be like the target population in as many ways as possible. It is especially important that the sample be representative in relation to the variables being studied and to other factors that may influence the study variables. A sample must be representative of the demographic characteristics, such as age, gender, ethnicity, income, and education, which often influence study variables. The accessible population must be representative of the target population. If the accessible population is limited to a particular setting or type of setting, the individuals seeking care at that setting may be different from those who would seek care for the same problem in other settings or from those who choose to use self-care to manage their problems. Representativeness is usually evaluated through comparison of the numerical values of the sample (a statistic such as the mean) with the same values from the target population.