Process for determining causality (sample size, bias, confounders)? Methods for controlling confounders (and when to use...

Process for determining causality (sample size, bias, confounders)? Methods for controlling confounders (and when to use them)?

Expert Solution

PROCESS OF DETERMINING CASUALTY:-
(A) Sample size:- this is calculated based on Z-score.
This is a constant value needed for this equation.

Sample size= (Z-score)^2 * StdDev*(1-StdDev) / (margin of error)^2

(B) Bias:- it is a systematic error in the design or data collection that results in a mistaken estimation of the true effect of the exposure and the outcome.
E.g. -selection bias
- information bias

(C) Confounding:- it is a situation in which association between an exposure and outcome is impaired by the presence of another variable.
This variable called confounder.
A confounder fulfill below conditions:-
        -It is a risk factor for the disease
        -It is not in the causal pathway between exposure and disease.
        -Confounding masks the true effect of a risk factor on a disease due to the presence of another variable.

METHODS OF CONTROLLING CONFOUNDERS:-
-Restriction
-Stratification
-Matching
-Regression
-Randomization

Nightingale answered 2 years ago

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