Performance of the lot quality assurance sampling method than L% (coverage rate below which the performance of an area will be considered inadequate) of use rates using HDSS data and Study area Pq is the proportion of CHW’s work-areas having less than L% of use rates derived using the LQAS technique. The above method was tested in Matlab, the study site of ICDDR,B. Matlab is situated approximately 55 km from Dhaka, the capital of Bangladesh. ICDDR,B has been a running a demographic surveillance system and a service-record system in Matlab for more than 25 years. The system involves monthly visits to households by female workers to collect information on births, deaths, marriage, and migration. In addition, they also provide immunization to children and family-planning sup- plies to couples of reproductive age. A computer-aided record-keeping system allows an accurate estimate of coverage rates for services they provide. The current population under surveillance is around 220,000. The area is divided into two with nearly half of the total population in one area. One of the areas has very inten- sive maternal-child health and family-planning (MCH- FP) services provided by ICDDR,B and the other half similar services by the Government of Bangladesh. The ICDDR,B services include home-delivery of fami- ly-planning supplies, EPI, distribution of oral rehydra- tion solutions, antenatal care and postnatal care serv- ices. Fifty-seven female Community Health Workers (CHWs) provide the services at the community level. Each CHW has a defined area to cover. The LQAS method was applied to identify the inadequately-per- forming CHW’s work-areas based on pre-defined thresholds of acceptability of DPT, measles, BCG, and contraceptive prevalence rate (CPR). Data collection Data for this study came from two sources: HDSS of 41 ICDDR,B and a cross-sectional survey following the LQAS methodology, later referred to as the LQAS survey. The latest coverage statistics by CHW’s work- areas were obtained from the HDSS database. During July-September 2002, a team of trained interviewers car- ried out the LQAS survey. A field supervisor, a stat- istician, and the principal investigator of the present study supervised the fieldwork. The updated HDSS list of households with their members was used as the sam- pling frame. In the LQAS survey, a systematic random sample of 30 children aged less than 24 months was selected from each CHW’s work-area for assessing the inadequacy in terms of use of DPT, measles and BCG vaccinations. Children receiving any of the DPT doses were consid- ered as having DPT. Similarly, 30 currently-married women of reproductive age, who were not pregnant at the time of the survey and with their husband living in the country, were systematically randomly selected for as- sessing the use of family-planning services. If any se- lected respondent was absent, a replacement was made from a socioeconomically similar neighbouring house- hold. Data analysis Lower and upper thresholds of service use for various indicators were decided based on current use rates of services by the target population reported by the HDSS. Table 2 shows the assumed different threshold levels for various indicators, maximum allowable individuals without any particular service to consider an area as in- adequate, the associated provider, and consumer risk. The CHW’s work-areas were classified as in- adequately performing using two approaches. First, us- ing the combination of the smallest sample size and the maximum number of non-users allowed yielding the least total misclassification error (consumer and provider risk less than 0.10) as shown in Table 2. Sec- ond, the most commonly-used sample sizes, such as 19 Table 2. Sample size, maximum allowed individuals to be adequate, and classification error Health service DPT Measles BCG CPR *CPR=Contraceptive prevalence rate Thresholds Lower (% of use) Upper (% of use) 65 60 65 50 95 90 95 80 Sample size 15 20 15 26 Maximum no. of non- users allowed 2 4 2 8 Probability of misclassification Provider Consumer 0.062 0.051 0.062 0.038 0.036 0.043 0.036 0.059 Total 0.098 0.094 0.098 0.087