Imagine that, in hypothetical study shown in table below, cases underestimated their exposure and, as a result, 20% of exposed cases were falsely categorized 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 type of misclassification random or systematic? Is it differential or nondifferential?
b) What effect would it have over the results of study? Draw up a two-by-two table displaying the misclassification, then determines estimates of the risk ratio for both true and the misclassified results and make comment on their difference to illustrate the effect.
