For some of your NURS classes, you'll have to evaluate if the research articles you find match the specific criteria your professor wants. You may be asked to find specific study types, or to identify the dependent and independent variables in a study. The pages of this guide describe some basic categories of articles and variables you might have to find or identify. Click on each page to learn more about how to recognize and differentiate these types of articles.
It's important to remember that these categories are not necessarily exclusive of each other. For example, a study can be a primary study, observational, retrospective, and longitudinal all at once. But also not every category will be relevant to every study.
Most of your sources will need to be primary sources. You can learn how to identify them on the Primary v. Secondary sources page.
Depending on the project, you may need to find sources that are observational or experimental. You can find out information about the differences on the Observational v. Experimental sources page.
These refer to the length of time that researchers observe participants. To find out how to identify the difference, visit the Cross-Sectional v. Longitudinal page.
The difference between prospective v. retrospective studies is whether the study's observation begins before or after differences among the participants are made/observed. To learn how to tell the difference go to the Prospective v. Retrospective Studies page.
In experimental studies you will find both independent and dependent variables. Researchers have control over introducing independent variables, while the dependent variables are the observed changes based on the introduction of the independent variable. More information about recognizing them is on the Independent v. Dependent Variables page.
The following information is a simple guide that can be used to determine the type of study you are looking at. Some studies may fit into more than one of these categories, so be sure to check and see what the best fit is.
When one participant is studied closely to get a detailed description of their condition and/or reaction(s) to treatment(s). These are likely referred to as case studies in the title and/or abstract, though you can also look in the methodology section. Information about the sample size should be mentioned in the methods. If there is only one participant, then the study is most likely a case study.
These are studies which include an independent variable introduced by the researchers. If you want to see if an article is a clinical trial, the best place to look is in the methodology section. To see how to recognize independent variables, go to the Independent v. Dependent Variables page.
When you compare two or more treatments, interventions, and/or outcomes, that is a comparative study. As with many other study types, checking the methodology section is the best way to determine if a source is a comparative study or not. It should mention some sort of comparison between the variables.
These are studies where the researchers do not assign interventions to the participants. The quickest way to determine if a source is observational is to look at the methods section. It should mention things along the lines of observing participants and there should be NO independent variables mentioned. To learn more about these studies, visit the Observational v. Experimental page.
Studies that involve an intervention of some sort are experimental studies. These should also include controlling for outside interference as much as possible. For more information on how to identify them, you can visit the page Observational v. Experimental.
Studies where independent variables are assigned randomly. These are always experimental in nature. If you want to determine if a study is a RCT or not, you can check the methods section to see if interventions were assigned randomly. More information about identifying variables is on the Independent v. Dependent Variables page.
These are studies where participants are observed at one point in time. You can find more information about how to determine if a study is cross sectional on the Cross-Sectional vs. Longitudinal studies page.
These are studies where participants are studied over a period of time. For more information, see our page on Cross-Sectional vs. Longitudinal studies page.
Much like the name suggests, quasi-experimental studies feature some aspects of experimental studies but not all. Some potential differences include not introducing an intervention, not controlling the variables well, or not using randomization for assigning interventions. To find out more about how to identify these studies, visit the Observational vs. Experimental studies page.
These pieces are where readers of the journal provide their opinion on recent articles or issues in the field. These readers are usually experts, and often they cite other studies and data to back up their points of view. However, these are not studies and they typically are not subjected to the peer review process.
Nursing theory is when an expert proposes a novel way of understanding events, environments, actions related to nursing. It offers a way of understanding why something is happening, or how things ought to be done. While these theories develop from years of nursing experience, observation, and research, they aren't studies themselves. Eventually, these theories are tested and applied in primary studies.
Have you ever found a source that appears to only be an abstract and nothing more? You probably came across a conference abstract. It describes a talk or poster given at a conference, but there's often no full text to be had. Although like a primary study, these often describe the methodology and results of a study the authors conducted, they don't provide enough information for them to be a good source for you to use in your papers for a class.
Research protocols describe a study that is being planned but hasn't actually been performed yet. These protocols provide a valuable way for researchers to document their processes and get feedback on their proposed study design, but the study itself hasn't been conducted yet.
There are essentially a type of study where other studies are consolidated into one report. They are often considered to be useful for determining best practices when treating patients. However, they will not work as a source for any project where you are supposed to use original studies. That said, you may find them to be useful for finding other studies mentioned in their references section.
