MPH 570 Module 2 Searching the Evidence Example

Asking the Right Question: Formulating and Searching for Public Health Evidence

Student Name

Master of Public Health Program, Aspen University

MPH 570: Evidence-Based Practice in Public Health

Instructor Name

Month Day, Year

Asking the Right Question: Formulating and Searching for Public Health Evidence

Finding relevant evidence begins long before typing words into a database. A clear, answerable question determines which sources to search and which studies matter. This paper explains how to formulate a public health question, structure it with a framework, build and document a search and decide when enough evidence has been found, using the question of how to reduce e-cigarette use among high school students.

Why Questions Matter

Broad questions such as what can be done about vaping return thousands of irrelevant results. Focused questions define the population, the intervention or exposure, the comparison and the outcome, making it possible to find and judge studies efficiently. They also help decision makers see exactly what the evidence addresses.

The PICO Framework

PICO stands for population, intervention, comparison and outcome. For the example: among high school students (population), do school-based prevention programs, retailer compliance checks or flavor restrictions (interventions), compared with no intervention or usual practice (comparison), reduce current e-cigarette use (outcome)? Adding study design and time frame creates PICOS.

Alternatives for Qualitative Questions

Some questions ask about experiences or perceptions rather than effects, such as why students begin vaping. A comparison study found that PICO searches were more sensitive, retrieving more relevant studies, while the SPIDER tool, which stands for sample, phenomenon of interest, design, evaluation and research type, was more specific but risked missing studies; the authors recommended PICO or PICOS for fuller searches when time allows (Methley et al., 2014).

Building the Search

Each PICO element becomes a search concept with synonyms and subject headings. The table shows the example.

Boolean Logic

Synonyms within a concept are joined with OR to broaden the search, and concepts are joined with AND to narrow it. Truncation, a symbol added to a word stem such as teen, captures variants like teens and teenager in databases that support it. Phrase searching with quotation marks keeps terms together. Filters for language, date and publication type can be applied but should be justified. Testing whether the search retrieves a few known key studies is a quick check that the strategy works.

Choosing Sources

PubMed covers biomedical and public health literature; other databases add behavioral science, education and policy research. Systematic review sources and evidence guides summarize studies; the Guide to Community Preventive Services uses explicit review methods to recommend population-based interventions (Briss et al., 2000). Gray literature, including government reports, surveillance data and evaluations by health departments, adds recent and practical evidence.

Documenting the Search

A good search is reproducible. Record the databases searched, the date, the full search strings, filters and the number of results at each stage. Reporting guidelines for systematic reviews ask authors to present the full search for at least one database and to show the flow of records from identification to inclusion (Page et al., 2021).

Screening and Managing Results

Results are screened first by title and abstract, then by full text, against inclusion criteria set in advance. Reference management software removes duplicates and stores citations. Keeping a log of reasons for exclusion makes the process transparent. Two reviewers screening independently, then resolving disagreements, reduce the chance that relevant studies are missed, though a single student may need to rely on careful criteria instead.

When Is a Search Complete

For a practice question, a search may be complete when new searches return mostly familiar studies, key systematic reviews have been found and their reference lists checked, and evidence covers the interventions and populations of interest. Full systematic reviews require more exhaustive searching than a health department's rapid review.

Searching for Local and Recent Evidence

Journals lag behind events. For a fast-changing issue like vaping, government surveillance reports, health department evaluations and professional association statements may contain the most current information. Searching agency websites and using news alerts for new reports supplement database searches.

Using Librarians

University and health sciences librarians are experts in search design. Consulting one early can improve the choice of terms, databases and filters, and many offer help to students and public health agencies. Their involvement also improves the documentation of the search.

Common Search Mistakes

Common mistakes include using too few synonyms, relying on a single database, applying filters that exclude relevant studies, forgetting subject headings and not recording the search. Another is stopping after finding a few supportive studies, which risks confirmation bias.

Organizing the Evidence

After screening, an evidence table listing each study's design, population, intervention, outcomes and key findings makes it easier to compare studies and appraise quality. The table becomes the foundation for the evidence review and later the capstone's literature section.

An Example Search String

A simplified PubMed search for the example might combine (adolescent OR teen OR youth OR high school students) AND (e-cigarette OR electronic cigarette OR vaping) AND (prevention OR school-based OR retailer OR flavor restriction OR policy). The student would refine it using subject headings and test whether known key studies are retrieved.

Time Management

Searching can expand endlessly. Setting a time limit, defining inclusion criteria before screening and deciding in advance which sources to search keep a practice review manageable. The documented method lets others judge its completeness.

From Search to Synthesis

A well-documented search feeds directly into appraisal and synthesis. Students should keep full citations, abstracts and notes on relevance for every included study, so that later modules can draw on them without repeating work.

Search Updates

Because evidence keeps growing, the search will be rerun before the capstone is finalized, using the same strings and sources, and any new studies added to the evidence table.

Conclusion

Evidence-based practice depends on well-built questions and systematic searches. Framing the youth vaping question with PICO, translating it into concepts, synonyms and subject headings, combining them with Boolean logic, searching both databases and gray literature and documenting every step produce a search that others can trust and repeat.

References

Briss, P. A., Zaza, S., Pappaioanou, M., Fielding, J., Wright-De Agüero, L., Truman, B. I., Hopkins, D. P., Dolan Mullen, P., Thompson, R. S., Woolf, S. H., Carande-Kulis, V. G., Anderson, L., Hinman, A. R., McQueen, D. V., Teutsch, S. M., & Harris, J. R. (2000). Developing an evidence-based Guide to Community Preventive Services: Methods. American Journal of Preventive Medicine, 18(1, Suppl.), 35-43. https://doi.org/10.1016/S0749-3797(99)00119-1

Methley, A. M., Campbell, S., Chew-Graham, C., McNally, R., & Cheraghi-Sohi, S. (2014). PICO, PICOS and SPIDER: A comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews. BMC Health Services Research, 14, Article 579. https://doi.org/10.1186/s12913-014-0579-0

Page, M. J., McKenzie, J. E., Bossuyt, P. M., Boutron, I., Hoffmann, T. C., Mulrow, C. D., Shamseer, L., Tetzlaff, J. M., Akl, E. A., Brennan, S. E., Chou, R., Glanville, J., Grimshaw, J. M., Hróbjartsson, A., Lalu, M. M., Li, T., Loder, E. W., Mayo-Wilson, E., McDonald, S., ... Moher, D. (2021). The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. BMJ, 372, Article n71. https://doi.org/10.1136/bmj.n71