What is the purpose of evidence-based research in nursing?

Choice A rationale

An autobiography is considered a primary source because it is a first-hand account written by the individual who lived the experiences or developed the theory. In a literature review, primary sources are preferred because they provide the original, uninterpreted words of the author. Using an autobiography allows the researcher to understand the theorist's direct perspective without the filter of another person's interpretation, which is the defining characteristic of a primary historical or theoretical document.

Choice B rationale

A secondary source is a document that discusses, summarizes, or evaluates information originally presented in another work. In this case, a summary and critique of a scholarly work involves an intermediary author interpreting the original investigator's findings. While secondary sources are helpful for gaining a broad overview of a topic or understanding how a theory has been received in the field, they are one step removed from the original data and the primary researcher.

Choice C rationale

An oral history is a primary source consisting of a recorded interview or account from a person with direct knowledge of historical events or research developments. Because the nurse researcher is providing their own direct testimony, the information is considered original evidence. Researchers use oral histories to capture personal insights and contextual details that might not be found in formal reports, but the direct nature of the communication keeps it in the primary category.

Choice D rationale

An investigator's report of their own research study is a primary source because it contains the original data, methodology, and results directly from the person who conducted the inquiry. This is the most common type of primary source used in nursing literature reviews to support evidence-based practice. Reviewing the original report ensures that the information is accurate and has not been distorted by the interpretations or biases of a third-party author or reviewer.

Choice A rationale

Statistical significance is a measure of the probability that the observed results occurred by chance, usually expressed as a p-value where p < 0.05 is the standard threshold. Using a homogeneous sample actually often makes it easier to achieve statistical significance because it reduces the variance within the data. By having participants who are very similar, the noise in the data is minimized, allowing the effects of the independent variable to be more clearly observed.

Choice B rationale

A homogeneous sample reduces the risk that findings are due to chance because it controls for extraneous variables that might otherwise confound the results. When the sample is uniform, the researcher can be more confident that the observed outcome is a result of the intervention rather than individual differences among participants. Increasing the similarity of the subjects strengthens internal validity, which actually decreases the likelihood that random error influenced the final statistical conclusions.

Choice C rationale

Generalizability, or external validity, refers to the extent to which the results of a study can be applied to other populations or settings. A homogeneous sample is very narrow, meaning the findings may only apply to individuals with those specific characteristics. This limits the utility of the research because it cannot be assumed that the same results would occur in a more diverse, real-world population. Broad application is hindered when the study group is not representative.

Choice D rationale

Reliability refers to the consistency and stability of a measurement over time. Using a homogeneous sample does not inherently decrease the reliability of the research instruments or the data collection process. In fact, testing a consistent group may lead to very stable and reproducible results within that specific context. Reliability is more closely related to the quality of the tools and the rigor of the procedures than to the diversity or uniformity of the participant pool.