Children are not goldfish—mark/recapture techniques and their application to injury data

Abstract

Objectives-Mark/recapture (or capturerecapture) is a simple technique commonly applied to estimate the hypothetical total (including undercount) in a register composed of cases from two or more independent and separately incomplete case lists. This paper seeks to illustrate serious drawbacks in the use of the mark/recapture technique when applied to injuries. Setting and subjects-Northumbrian children under 15 years of age who were seriously injured in motor vehicle accidents (MVAs) over a five year period ascertained from two data sources: police reports and hospital inpatient records. Methods-Individuals (n) appearing in both police (S) and hospital (H) case lists are identified using various matching criteria. The separate and combined influence of age, sex, and casualty class (cyclist, passengers, pedestrians) on the probability of such matching is estimated using multivariate techniques. The hypothetical total incidence of child MVA victims (N) is calculated from N = (S × H)/n. Main outcomes-Estimates of the incidences of "serious" injuries in MVAs under various conditions of stratification and matching. The overall procedure is tested for conformity with accepted criteria for valid use of mark/recapture. Results-About one third of the 1009 police and 836 hospital records could be exactly matched. There were significant variations in matching proportions by class of accident (pedestrian v passenger v cyclist). This selective recapture or "heterogeneity" was not aVected by sex, but was independently influenced by the age of the child. Further uncertainty was introduced when matching criteria were slightly relaxed. Estimates of the total population of children with serious injuries vary accordingly from 1729 to 2743. A number of plausible reasons why these two data sources might not be unbiased or mutually independent samples of the total target population are proposed as explanations for this heterogeneity.Conclusion-This typical example of two sample mark/recapture estimation in an epidemiological setting can be shown to violate virtually all the requirements for valid use of the technique. Very little can be deduced accurately about the scale or characteristics of an unobserved group by the use of mark/recapture applied to two overlapping health event registers. (Injury Prevention 2000;6:46-50)

Measuring and maximizing coverage in the World Trade Center Health Registry

“…Some companies were within the media reach of the WTCHR while others were outside. Several critiques of the application of capture-recapture to epidemiological studies have been made, with suggestions for refinement [15]. These critiques emphasize the fact that cases must be intensively scrutinized in an attempt to identify those characteristics that might act to exclude a case from one list or another.…”

Estimating road traffic mortality more accurately: Use of the capture–recapture method in the West Azarbaijan Province of Iran

“…In the current study, these two sources were combined and a capturerecapture method was employed to determine actual fatal RTI rates. In the published literature, the capturerecapture method has been used a number of times to assess mortality and morbidity due to RTI; the data sources employed include police reports, hospital registers, ambulance records and official statistics (Roberts & Scragg, 1994;Razzak & Luby, 1998;Aptel et al, 1999;Jarvis et al, 2000;Morrison & Stone, 2000;Tercero & Andersson, 2004;Amoros et al, 2006;Meuleners et al, 2006;Van et al, 2006).…”

Estimating crashes involving heavy vehicles in Western Australia, 1999–2000: A capture–recapture method

“…The method has become increasing popular for estimating hidden populations, such as illicit drug users (Frischer et al, 1993) and the homeless (Fisher et al, 1994). A few studies have also adopted this approach for injury prevention (Razzak and Luby, 1998;Jarvis et al, 2000).…”