1 / 19

Data Collection Principles

Data Collection Principles. By Farrokh Alemi, Ph.D. Sampling. Examine a subset of cases . Randomization. Examine a subset of cases . Non-response Bias. Angry patients do not take satisfaction surveys. Convenience Bias. Confounding Variable. Real Cause. Presumed Cause. Effect.

lynda
Download Presentation

Data Collection Principles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Data Collection Principles By Farrokh Alemi, Ph.D.

  2. Sampling Examine a subset of cases

  3. Randomization Examine a subset of cases

  4. Non-response Bias Angry patients do not take satisfaction surveys

  5. Convenience Bias

  6. Confounding Variable Real Cause Presumed Cause Effect

  7. Confounding Variable Fire Firemen on scene Burning house

  8. Blaming Heroes Severity of Illness Medication Treatment Patient Outcomes

  9. Think it Through Supposed 10% of patients report their attitudes on the web and 40% of patients who write a comment on web are negative, what percent of our patients are dissatisfied?

  10. Think it Through 0.06% 60% 40% 10% 0.04% 90% 0.54% 60% 40% 0.46%

  11. Think it Through 40% 10% 90% 60%

  12. Oops

  13. Observational Studies

  14. Retrospective Studies Investigator Cases Exposed Outcomes Outcomes Controls not Exposed Past Future Time Present

  15. Retrospective Studies Investigator Cases Exposed Outcomes Outcomes Controls not Exposed Past Future Time Present

  16. Implied Equivalence Investigator Cases Exposed Outcomes Matched Otherwise Outcomes Controls not Exposed Past Future Time Present

  17. Vioxx Study

  18. Take Home Lesson In observational studies, controls are matched to cases in all relevant variables except for exposure to treatment

  19. Do One: Identify cases. Select two controls that match on age & have lowest random number. Calculate the proportion of success for case and matched controls

More Related