Science of Practice

Question 1

The time between a condition being identified by screening and a condition becoming clinically apparent = ?

Answer 1

Lead time

Question 2

The time between an intervention being assessed as clinically useful and an intervention actually entering everyday practice = ?

Answer 2

Lag time

Question 3

Percentage of those with a condition who correctly test positive =?

Answer 3

Sensitivity

Question 4

Percentage of those without a condition who correctly test negative = ?

Answer 4

Specificity

Question 5

Odds of a positive test result in an affected individual compared with a positive result in an unaffected individual = ?

Answer 5

Likelihood ratio

• this is a positive likelihood ratio

Question 6

Number of patients who would need to have an intervention for a set outcome to be shown in one of them = ?

Answer 6

Number needed to treat

Question 7

Total number of cases in a population at any one time (expressed as a proportion of the total population) = ?

Answer 7

Prevalence

Question 8

Rate at which new cases of a condition occur in a population (over a set period of time - usually 1 yr) =?

Answer 8

Incidence