Ruth Lilly Medical Library

EER (Experimental Event Rate) = .001 ​

“The risk of developing melanoma over 20 years in the (sunscreen) experimental group was 0.1% or 1 in 1000.” OR “The proportion of those who developed melanoma over 20 years in the sunscreen group was 1 out of 1000.” OR “The rate of developing melanoma in the sunscreen group was 0.1%” ​

CER (Control Event Rate) = .005 ​

“The risk of developing melanoma over 20 years with placebo is 0.5%.” ​

ARR (Absolute Risk Reduction) = EER-CER = .004 (Absolute Risk Increase is the opposite) ​

“Sunscreen use reduces the absolute risk of developing melanoma by 0.4%.” OR “0.4% of patients, or 4 of 1000, are preventing from developing melanoma by using sunscreen.” OR “For every 1000 patients using sunscreen, 4 cases of melanoma are averted.” ​

NNT (Number-needed-to-treat) = 1/ARR = 250 ​

“250 patients would need to be treated with sunscreen rather than placebo for 20 years to prevent one additional case of melanoma.” NNH is the opposite. ​

RR (Relative Risk or Risk Ratio) = EER/CER = .20 ​

• “People who use sunscreens for 20 years have less than a fifth of the risk of developing melanoma of those who use a placebo. Alternatively, people who do not use sunscreens have a 5 times greater risk of developing melanoma over 20 years as compared to those who use sunscreens.” OR “The risk of melanoma without sunscreen is 5 times the risk with sunscreen.” ​
• “The rate of melanoma with sunscreen is 20% of the rate without sunscreen.” OR Risk remaining: “Just 20% of the original risk of developing melanoma remains for those who use sunscreen.” ​

RRR (Relative Risk Reduction) = (EER-CER)/CER or 1 – RR = .80 ​

“Sunscreen use decreases the risk of developing melanoma by 80% compared with no sunscreen.” OR Risk removed: “80% of the risk of developing melanoma is removed by using sunscreen.” ​

Duke Program on Teaching Evidence-Based Practice  - https://sites.duke.edu/ebmworkshop/

Sensitivity - The proportion of people with a positive test result among those with the target condition. (Sn)out – a negative highly sensitive diagnostic test rules out the disease. ​
Specificity – The proportion of people with a negative test result among those without the target condition. (Sp)in – a positive highly specific diagnostic test rules in a disease. ​
Likelihood ratios (- and +) – Used with pretest probability and a nomogram to determine post-test probability. ​
Predictive Value - There are 2 categories of predictive value. Positive predictive value is the proportion of people with a positive test result who have the disease; negative predictive value is the proportion of people with a negative test result and who are free of disease. These are influenced by prevalence.  ​

From JAMAEvidence - https://ulib.iupui.edu/cgi-bin/proxy.pl?url=https://jamaevidence.mhmedical.com ​