Judging the evidence part 2

I previously reported on a lecture slide deck called ‘Judging the Evidence’ by Adrian Sleigh for a course PUBH7001 Introduction to Epidemiology, April 30, 2001. http://ivanhanigan.github.com/2015/11/judging-the-evidence-using-a-literature-review-database

I have also now extracted several slides into a template outline for reviewing epidemiological and other research.

Adrian Sleigh’s Protocol

Object of Study, Hypotheses or Research Questions

1. Purpose of Study: Objectives of study; why was it done?
2. Reference Population:
   • To whom do authors generalize results?
   • To whom should the findings be generalized?

Sampling

From the Reference Pop (target population) ->

Source Pop -> Eligible population

` The source population may be defined directly, as a matter of defining its membership criteria; or the definition may be indirect, as the catchment population of a defined way of identifying cases of the illness. The catchment population is, at any given time, the totality of those in the ‘were-would’ state of: were the illness now to occur, it would be ‘caught’ by that case identification scheme Source: Miettinen OS, 2007 http://www.teachepi.org/documents/courses/fundamentals/Pai_Lecture6_Selection%20bias.pdf `

Sample Pop:

1. Refusals, Dropouts
2. Participants -> Study Pop

Design of study

1. Study setting: Where and when was the study done? What were the circumstances? Ethics?
2. Type of study: Experimental vs natural, descriptive vs analytical (trial, cohort, case-control, prevalence, ecological, case-report, etc). If case-control or cohort, was the timing of data collection retrospective or prospective?
3. Subjects: Who (number, age, sex, etc.)? How were they selected?
4. Comparison groups: What control group or standard of comparison? How appropriate?
5. Study size: Was the sample size adequate to give you confidence in the finding of “no association
6. Bias and Confounding
   • a) Selection bias: Were groups comparable for subjects who entered and stayed in study? Selection influenced by exposure (c-c) or effect (cohort) under study? Drop-outs?
   • b) Confounding: Control of potential confounding variables in design of the study - matching or subject restriction?

Observations

1. Procedure: How are the variables in the study defined and measured, ie how were data collected?
2. Definition of terms: Are definitions of diagnostic criteria, measurements and outcome unambiguous? Could be reproduced?
3. Bias and Confounding
   • a) Observation bias: Were study groups comparable for measurements or mode of observation? Mis-classification in determining exposure or disease categories? Differential between groups, or ‘random’?
   • b) Confounding: Information recorded on variables that could confound the association under study (to permit adjustment in the analysis)?

THANKS Prof Sleigh!