A way of combining data from many different research studies. A meta-analysis is a statistical process that combines the findings from individual studies. Example:
Preyde, M., & Synnott, E. (2009). Psychosocial intervention for adults with cancer: A meta-analysis. Journal of Evidence-Based Social Work, 6(4), 321–347. https://doi.org/10.1080/15433710903126521
A summary of the clinical literature. A systematic review is a critical assessment and evaluation of all research studies that address a particular clinical issue. The researchers use an organized method of locating, assembling, and evaluating a body of literature on a particular topic using a set of specific criteria. A systematic review typically includes a description of the findings of the collection of research studies. The systematic review may also include a quantitative pooling of data, called a meta-analysis. Example:
Allen-Meares, P., Montgomery, K. L., & Kim, J. S. (2013). School-based social work interventions: A cross-national systematic review. Social Work, 58(3), 253–262. https://doi.org/10.1093/sw/swt022
A controlled clinical trial that randomly (by chance) assigns participants to two or more groups. There are various methods to randomize study participants to their groups. Example:
Kim, J. S., Brook, J., & Akin, B. A. (2018). Solution-focused brief therapy with substance-using individuals: A randomized controlled trial study. Research on Social Work Practice, 28(4), 452–462. https://doi.org/10.1177/1049731516650517
A clinical research study in which people who presently have a certain condition or receive a particular treatment are followed over time and compared with another group of people who are not affected by the condition. Example:
Cagle, J. G., Lee, J., Ornstein, K. A., & Guralnik, J. M. (2020). Hospice utilization in the United States: A prospective cohort study comparing cancer and noncancer deaths. Journal of the American Geriatrics Society, 68(4), 783–793. https://doi.org/10.1111/jgs.16294
Case-control studies begin with the outcomes and do not follow people over time. Researchers choose people with a particular result (the cases) and interview the groups or check their records to ascertain what different experiences they had. They compare the odds of having an experience with the outcome to the odds of having an experience without the outcome. Example:
Persaud, N., Coleman, E., Zwolakowski, D., Lauwers, B., & Cass, D. (2012). Nonuse of bicycle helmets and risk of fatal head injury: a proportional mortality, case-control study. Canadian Medical Association Journal, 184(7), E921–E923. https://doi.org/10.1503/cmaj.120988
The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously. Example:
Enns, A., Eldridge, G. D., Montgomery, C., & Gonzalez, V. M. (2018). Perceived stress, coping strategies, and emotional intelligence: A cross-sectional study of university students in helping disciplines. Nurse Education Today, 68, 226–231. https://doi.org/10.1016/j.nedt.2018.06.012
A report on a client or series of clients (or patients) with an outcome of interest. No control group is involved. Example:
Tenorio, A. C., Johnson, C., & Grudier, S. (2021). End of life during the COVID19 pandemic - Highlighting the role of a dedicated palliative care social worker during this time of crisis. Journal of Social Work in End-of-Life & Palliative Care, 17(2-3), 98–103. https://doi.org/10.1080/15524256.2020.1830922
Put forth by experts in the field. Example:
Koop C. E. (2006). Health and health care for the 21st century: for all the people. American Journal of Public Health, 96(12), 2090–2092. https://doi.org/10.2105/AJPH.2006.098962
Studies conducted using animal subjects. Example:
Schulz, C., Paulus, K., Jöhren, O., & Lehnert, H. (2012). Intranasal leptin reduces appetite and induces weight loss in rats with Diet-Induced Obesity (DIO). Endocrinology, 153(1), 143–153. https://doi.org/10.1210/en.2011-1586
"Test tube" experiments conducted in a controlled laboratory setting.
Adapted from Oxford University's Centre for Evidence-Based Medicine: Study Designs and Glossary of EBM Terms.
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