1) Consider that, in the hypothetical study given in the table below, cases underestimated their exposure and, as a result, 20% of exposed cases were falsely classified as unexposed, however that the classification of controls was not affected.
True results of the hypothetical case-control study with no measurement error.
|
|
Cases
|
Controls
|
Total
|
|
Exposed
|
300
|
250
|
550
|
|
Unexposed
|
100
|
150
|
250
|
|
Total
|
400
|
400
|
800
|
Explain whether this kind of the misclassification is random or systematic? Specify is it differential or non-differential?
b) Specify the effect it would have on the results of study?