Exposure/Disease Relation Calculators

File Name
(Click hold mouse button, select "save as" to Download)

Calculator Name

Function of Calculator

exposdis.xls

 

Web Calculator (CEBM)

Contingency table showing outcomes (disease) as an effect of exposure

You specify data about the relation between exposure and disease, it produces statistics (relative risk, etc.)

NNP.xls

Number Needed to Protect

You specify the effect of an exposure (probability of bad outcome without the exposure and with the exposure), it produces the number of people you would need to protect to prevent one bad outcome.

NNPcost.xls

Number Needed to Protect and Cost

You specify the effect of an exposure (probability of bad outcome without the exposure and with the exposure), it produces the number of people you would need to protect to prevent one bad outcome. You specify the cost of protecting one person from exposure. It says whether it is worth protecting a person from exposure, and gives thresholds on NNP and Cost of Protecting.

Odds-Rat.xls

Odds ratio: contingency between treatment or exposure and outcome

You specify the contingency table, it calculates odds ratio. Allows this to be done from various starting points.

2trtindp.xls

2 Treatment Independence

To explore dependencies between exposure to two risk factors or treatments. One dependency is correlation between the factors. The other dependency is the effects of one factor being different for different levels of the other factor.

2trtindpKram.xls

 

Tutorial

2 Treatment Independence, diagnosis framework

To explore dependencies between exposure to two risk factors or treatments. This follows Kraemer et al (1999 Psychological Methods) in speaking of the "sensitivity" and "specificity" of the risk factor for the outcome. In calculation, it is identical to the 2 Test Independence calculator (see above) and so you can use that one's tutorial. The dependencies are the correlations between the two risk factors' false negatives, and between their false positives.