Nursing Professional Development Certification (NPD-BC) Practice Exam

Which sampling method in evidence-based research is most likely to introduce bias?

1. Purposive

2. Quota

3. Convenience

4. Snowball

The correct answer is: Convenience

The convenience sampling method is most likely to introduce bias because it involves selecting individuals who are easily accessible or readily available to the researcher. This approach does not ensure that the sample is representative of the broader population, which can lead to results that are not generalizable. For example, if a researcher only surveys people who are present in a specific location at a specific time, the resulting data may reflect the experiences or opinions of that limited group rather than the population as a whole. Consequently, findings derived from convenience sampling can be skewed, potentially impacting the validity of the research conclusions. In contrast, purposive sampling targets specific characteristics or criteria to recruit participants intentionally, aiming for a sample that reflects particular qualities of interest. Quota sampling sets out to meet specific demographic criteria, thus attempting to ensure representation. Snowball sampling relies on referrals from participants, which can sometimes help uncover hidden populations but may still introduce a level of bias linked to the network of individuals initially contacted. While these methods can also have limitations, convenience sampling stands out as particularly prone to bias due to its reliance on availability rather than strategic selection.