Rob van Hest Capture-recapture Methods in Surveillance - RePub ...

Methodology of capture-recapture analysis
2.2 Application and limitations of capture-recapture analysis for
epidemiological studies
2.2.1 Introduction
Several steps are important in planning, applying, presenting and evaluating capturerecapture
techniques in epidemiological studies: 43,44
1. The purpose of the study and the required accuracy of the data should be described.
2. Appropriate sources for capturing cases should be selected.
3. Possible relationships between the selected sources should be investigated and described
as well as their influence on the capture-recapture results.
4. An unambiguous and uniform case-definition for the various sources should be used.
5. The accuracy of diagnosis and disease classification in each of the sources should be
examined.
6. The accuracy of record-linkage should be described.
7. The case-ascertainment, the distribution of the cases over the various registers, the
selected capture-recapture model and the estimate of the number of missing cases, and
thus the total number of cases, should be given, from which prevalence or incidence
rates can be calculated.
8. The limitations of the capture-recapture methodology in epidemiology should be
addressed.
Preferably preparatory fieldwork and explorative research should be performed, if
possible including a small scale pilot capture-recapture study investigating feasibility,
limitations and costs, ideally with the possibility of validation of the estimates against known
data from a census or survey. 59 This preparation is still required while planning a capturerecapture
study on a particular disease when such a study was performed successfully in the
past or elsewhere, using similar data sources and resulting in a fitting capture-recapture model
that produced a credible estimate. In the past and abroad, the characteristics of disease
registers, legislation or guidelines and organisation of disease diagnosis and surveillance may
be different. Consultation of a statistician, either a bio-statistician or social scientist, with
experience in capture-recapture analysis should be part of the planning of a capture-recapture
study. In case of investigating large data sources collaboration with a data manager with
experience in sophisticated computerised record-linkage is required.
2.2.2 Purpose and required accuracy of the study
The aim of the study and the intended use of the reported estimates should be described,
including the likely consequences for utilisation of under-estimates or over-estimates.
Some objectives need accurate estimates while others accept under-estimates or overestimates
serving as the upper or lower bound of the true population size. 7
2.2.3 Source-selection and number of sources
Selection of suitable data sources from the available information sources is needed in
order to obtain valid capture-recapture estimates. 45,46 Potential data sources can be
identified from the literature or the experience from other researchers. All cases should
have a chance to be recorded in each one of the selected data sources. All selected data
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