Application of Capture-Recapture Methods for Estimating the Population Size of Street Children in Taraba State, Nigeria

Abstract

This study investigated the street-child phenomenon and the applicability of capture-recapture (C-R) methods for estimating such hard-to-count populations. The method was applied to estimate the number of street children in Taraba State, Nigeria. Primary data were collected using a purposive sampling design, with five wards chosen as strata from Jalingo, Gassol and Wukari Local Government Areas. The data obtained were coded, cross-matched according to specific matching criteria and a degree of matching. Four C-R models were employed: the Model with Non-Factor Interaction Effect (M_o), Petersen Model (M_s), Listability Model (M_o) and Behavioral Response Model (M_b). The behavioral response model (M_b) performed best in all the selected wards with lowest AIC (Kona ward, AIC = 5.1229, Barade ward, AIC = 5.9221, Sintiari ward, AIC = 6.1743, Kachalla-Sembe ward, AIC = 5.5345 and Mayogwoi ward, AIC = 5.1400); for Gassol LGA, (M_s) model performed best in Sandirde with AIC = 5.9322 while behavioral response (M_b) model was most efficient in Mutum biyu I, Mutum biyu II, Nannai and Tutare wards (AIC = 5.4511, 5.0165, 4.3838 and 4.9032, respectively); for Wukari LGA the Petersen model (M_s) model performed best in Avyi, Bantaje and Hospital wards (AIC = 6.2922, 6.1837, 6.1930) respectively while, behavioral response model (M_b) model performed best in Kente and Puje wards (AIC = 5.6010, 5.4224), respectively. Accordingly, the estimated numbers of street children per ward using the best-fitting model were: for Jalingo LGA: Kona ward, N = 101, Barade ward, N = 160, Sintiari ward, N = 185, Kachalla-Sembe ward, N = 128 and Mayogwoi ward, N = 102. The estimated total number of street children in Jalingo LGA is 676; for Gassol LGA: Sandirde ward, N = 161, Mutum biyu I ward, N = 122, Mutum biyu II ward, N = 95, Nannai ward, N = 66 and Tutare ward, N = 189. The estimated total number of street children in Gassol ward is 533; for Wukari LGA: Avyi ward, N = 198, Bantaje ward, N = 186, Hospital, N = 187, Kente ward, N = 133 and Puje ward, N = 120. The estimated total number of street children in Wukari LGA is 824. This study demonstrates that capture-recapture methods can effectively estimate the size of elusive or difficult-to-count populations.