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Public Health: Subject Guide: About Study Designs

Research resources for Public Health.

Types of Study Designs

Meta-Analysis

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:
Conn, V. S. (2010). Anxiety outcomes after physical activity interventions: meta-analysis findings. Nursing research59(3), 224.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Systematic Review

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:
Wanchai, A., Armer, J. M., & Stewart, B. R. (2010). Complementary and Alternative Medicine Use Among Women With Breast Cancer: A Systematic Review. Clinical Journal of Oncology Nursing14(4).

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Randomized Controlled Trial

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:

Barrett, B., Hayney, M. S., Muller, D., Rakel, D., Ward, A., Obasi, C. N., ... & West, R. (2012). Meditation or exercise for preventing acute respiratory infection: a randomized controlled trial. The Annals of Family Medicine10(4), 337-346.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Cohort Study (Prospective Observational Study)

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:

Croucher, R., Shanbhag, S., Dahiya, M., Kassim, S., Csikar, J., & Ross, L. (2012). Smokeless tobacco cessation in South Asian communities: a multiā€centre prospective cohort study. Addiction107, 45-52.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Case-control Study

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. CMAJ184(17), E921-E923.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Cross-sectional study

The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.

Example:

Steiner, M. J., Skinner, A. C., & Perrin, E. M. (2011). Fasting might not be necessary before lipid screening: a nationally representative cross-sectional study. Pediatrics128(3), 463-470.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Case Reports & Series

A report on a series of patients with an outcome of interest. No control group is involved.

Example:

Lattanzi, J. B., Campbell, S. L., Dole, R. L., & Palombaro, K. M. (2011). Students mentoring students in a service-learning clinical supervision experience: an educational case report. Physical Therapy91(10), 1513-1524.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Ideas, Editorials, Opinions

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):2090-2.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Animal Research Studies

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). Endocrinology153(1), 143-153.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Test-Tube Lab Research

"Test tube" experiments conducted in a controlled laboratory setting.

Adapted from Study Designs; in NICHSR Introduction to Health Services Research: a Self-Study Course

Levels of Evidence

The Evidence Pyramid is often used to illustrate the development of evidence. At the base of the pyramid is animal research and laboratory studies - this is where ideas are first developed. As you progress up the pyramid the amount of information available decreases in volume, but increases in relevance to the clinical setting.


http://libraryguides.unh.edu/health-literacy.  Adaptation of the Evidence Pyramid Diagram
developed by the Medical Research Library of Brooklyn, SUNY Downstate Medical Center

Clinical Filters

What type of question are you asking and which would be best to support the evidence?

Type of Question Type of Study/Methodology to Look at
Therapy

Double-Blind Randomized Controlled Trial;
Systematic Review/MetaAnalysis of RCT

Diagnosis Controlled Trial;
Systematic Review/Meta Analysis of Controlled Trial
Harm Cohort studies
Prognosis Cohort Studies;
Case control, case studies
Etiology Cohort studies
Prevention Randomized Controlled Trial;
Cohort studies
Quality Improvement Randomized Controlled Trial
Quality of Life Qualitative Study
Cost Effectiveness Economic Evaluation
Clinical Exam Prospective, blind comparison to gold standard