In a nested case-control study where controls are selected using incidence density sampling, this procedure estimates the incidence rate ratio which, given the rarity of the disease, is roughly equal to the odds ratio.
Controls were selected by incidence density sampling.
Controls with no GPRD record of pancreatic cancer were selected using incidence density sampling and matched to cases on year of birth, sex and general practice site.
The controls will be selected using incidence density sampling and allocated an index date, which is the date on which their matched case was first diagnosed with VTE.
Population controls with no history of previous respiratory cancer were randomly selected through incidence density sampling from residential telephone directories (Rothman and Grennland, 2008).
For each case, two controls matched on age and date and time of day of blood collection were selected using incidence density matching.
Up to ten controls per case were selected by incidence density sampling and matched to cases on age, sex and follow-up time.
From this (uncertain) human variability distribution, we derive an (uncertain) human variability factor HV I* for the ratio between the quantile corresponding to a selected target incidence (I*) value and the median, so that HD M* I* = HD M* × HV I*.
A total of 10 controls were selected using incidence density sampling, that is, the controls were residents in North Jutland County, alive and at risk for a first hospital admission for breast cancer at the time the corresponding case was diagnosed, but could be subsequently diagnosed as a case.
Controls had originally been selected by incidence density sampling from all cohort members alive and free of cancer at the time of diagnosis of the cases and were matched by age, sex, time of day at blood collection, and fasting status at the time of blood collection.
