Biostat

Evidence-Based Medicine

1. Ask question

2. Find evidence

3. Assess/Appraise evidence

4. Apply evidence

Scientific Method

1. Make observation

2. Ask research question

   • PICO:

   • Patient Problem

   • Intervention, prognostic factor or exposure

   • Comparison

   • Outcome

3. Perform literature search

4. Reassess research question

5. Construct hypothesis

6. Conduct experiment to test hypothesis

7. Collect and analyze data

   • Primary

     • Collect data specifically to answer research questions

     • Engage the subject directly in some fashion

       • Self-reports (surveys/interviews), observations (obtrusive or unobtrusive), biological assessments (laboratory tests)

     • Often used in prospective studies

   • Secondary

     • Uses data already collected for other purposes; examples include medical charts and medical claims

     • Often used in retrospective studies

8. Draw conclusion

   • rejecting or failing to reject the null hypothesis

     

Independent variable:

• a variable that is manipulated by the experimenter to determine its effects on the dependent variable

Dependent variable:

• the outcome variable that we hypothesize will be related to, or caused by changes in the independent variable

Confounding variable:

• a type of extraneous variable (a variable that is not the focus of the study) that is not controlled for and can have an impact on the independent and/or dependent variable

Random Assignment

• Every participant has an equal chance of being assigned to any of the groups or experimental conditions of the study