Nursing Research Guide
A guide for conducting nursing research at KUMC.
Please refer to your textbook and/or faculty member with more information on these topics. This guide does not provide exact instructions on understanding study designs and the levels of evidence.
| Quality Guides |
|---|
| A - High Quality: Consistent, generalizable results; sufficient sample size for the study design; adequate control; definitive conclusions; consistent recommendations based on comprehensive literature review that includes thorough reference to scientific evidence |
| B - Good Quality: Reasonably consistent results; sufficient sample size for the study design; some control, fairly definitive conclusions; reasonably consistent recommendations based on fairly comprehensive literature review that includes some reference to scientific evidence |
| C - Low Quality or Major Flaws: Little evidence with inconsistent results; insufficient sample size for the study design; conclusions cannot be drawn |
- Types of Study in Medical ResearchRöhrig, B., du Prel, J. B., Wachtlin, D., & Blettner, M. (2009). Types of study in medical research: part 3 of a series on evaluation of scientific publications. Deutsches Arzteblatt international, 106(15), 262–268. https://doi.org/10.3238/arztebl.2009.0262
- How to Choose Your Study Design ArticleMellis, C.M. (2020), How to choose your study design. J Paediatrics and Child Health, 56: 1018-1022. https://doi.org/10.1111/jpc.14929
- Critical Appraisal Tools - CEBMCritical appraisal worksheets to help you appraise the reliability, importance and applicability of clinical evidence by the Centre for Evidence-Based Medicine (CEBM).
- CASP Critical Appraisal ChecklistsFree downloadable checklists to help you more easily and accurately perform critical appraisal across a number of different study types.
Observational Designs
- Case Reports and Case StudiesCase reports and case series provide detailed descriptions of cases without the use of a control group. The possible association between the observed outcome and a specific exposure is described based on clinical evaluations and histories of a single subject (case report) or a small group of subjects (case series). These study designs may be the first in identifying a new disease or adverse health effect from an exposure. The results of these fast and inexpensive studies are helpful in generating hypotheses that may later be studied with other study designs but are rarely useful to establish causal effects (Noordzij, 2009).
- Case-Control StudiesThis design is always retrospective and is conducted by comparing two groups: one group with the disease (cases) and another group without the disease (controls). Its aim is to find out the odds of having a risk factor or an exposure if an individual has a specific disease (Odds ratio) (Abbas, 2021). These studies require a relatively small sample size, and is therefore an efficient design, particularly in case of rare outcomes (Noordzij, 2009).
- Cross-Sectional StudiesExposure and outcome are measured at the same moment, so it is usually not possible to distinguish whether the exposure preceded or followed the outcome. Thus, cause and effect relationships are not certain (Noordzij, 2009). These studies can calculate the frequency of disease (prevalence) or the frequency of a risk factor (Abbas, 2021).
- Cohort StudiesIn a cohort study, an investigator defines a study population (cohort) consisting of subjects who are free of the outcome of interest. A cohort study enables investigators to study multiple outcomes as well as multiple exposure variables. Cohort studies can be inefficient because it may take a long time before an outcome occurs and, as a result, these studies can be rather expensive (Noordzij, 2009). This design is the strongest among the observational studies. These studies approach by this study by 2 longitudinal designs:
Prospective: follow the individuals in the future to know who will develop the disease
Retrospective: look to the past to know who developed the disease (e.g. using medical records) (Abba, 2021)
Randomized Control Trials (RCTs)
- Randomized Control StudyStudy investigators do not assign the exposure or intervention that participants receive (Zabor, 2020).
- Randomized Intervention StudyParticipants are assigned to receive a certain intervention according to a prespecified research plan and are then followed up prospectively to observe the outcome of interest (Zabor, 2020).
