This document discusses how to identify the type of study presented in a research paper. The key types are experiments, which measure outcomes in a controlled setting, and trials, which test interventions in real-world patients. The most important question to determine the type of study is whether there is an intervention that could affect patients. Common study designs in radiology research are observational studies, reader studies, and randomized controlled trials.

1. How to read a research paper (part 1)
What sort of study is it?

2. Research starts with a question
Identify the “primary” research question
• Usually in the last line of the introduction.
• Many journals now have structured abstracts/summaries.
• Varies by field.
• Some authors don’t ever clearly state what the paper is about.

3. Research starts with a question

4. Who is the research for?
Doctors? Researchers? Others (administrators, economists, statisticians, etc.)?

5. What sort of study is it?
IRRELEVANT

6. Types of studies
Two main types of studies:
• Experiments
• Trials
Experiments are to measure things, trials are to try things.

7. Types of studies
Experiments answer “in a controlled setting, can we measure a difference
between A and B?”
Trials answer “in the real world, what happens to patients if we try A or B?”

8. Types of studies
The dividing line is the intervention. An experiment measures something but
doesn’t change what happens to patients.
Three commonly use designs in radiology research are the observational study
(usually cohort or case-control studies), the reader study, and the randomised
controlled trial.
Observational study Reader study RCT
Experiment Trial

9. Observational studies
An observational study takes a group of things (patients, images, mice, etc.) and
measures (observes) something about them, for example how often a particular
imaging finding occurs in a CT study.
Observational study Reader study RCT
Experiment Trial

10. Reader studies
A reader study compares two different sets of readers (usually radiologists), for
example comparing radiologist sensitivity and specificity for detecting a disease
using CT vs MRI.
Observational study Reader study RCT
Experiment Trial

11. Randomised controlled trials
An RCT looks at the difference in patient outcome with and without an
intervention. For example, determining the complication and morbidity rate if
the thrombolysis window is extended to 10 hours.
Observational study Reader study RCT
Experiment Trial

12. What sort of study is it?
Most important question: Is there an intervention that will affect patients?