Which of the following describes "selection bias"?

Selection bias occurs when certain individuals or groups are chosen for a study based on specific characteristics, which can lead to results that are not representative of the broader population. This can compromise the validity of a study's findings because the sample may not accurately reflect the diversity or the true distribution of the target population.

For instance, if a researcher selects participants who only meet certain criteria, like being of a specific age or health status, the results may not be applicable to those outside this group. This is critical in nursing research, where understanding the effects of interventions across varied populations is essential for generalizability and effectiveness in practice.

In contrast, the other options describe different concepts. Inconsistent methods across data collection refer to variability in how data is gathered, which may lead to inconsistencies but not specific to the selection process. External events impacting participants during a study can introduce confounding variables but do not describe how participants are chosen. Variation in participant responses over time reflects changes in responses but does not pertain to the selection stage.