If the logbook from health centres are accurately detecting all health care service delivery events and there are sound estimates of relevant population denominators from data collection of population sources by VHVs, the values for indicators derived from the HMIS and MCH-EPI should be similar to those derived from VHVs and the health centre administrative data.
The international data we discuss vary in terms of population sizes, age ranges, time periods, data collection methods, population coverage and survival analysis methods.
The review by Oen and Cheang [ 34] revealed that reports of the descriptive epidemiology of chronic arthritis in childhood differ in methods of case ascertainment, data collection, source population, geographic location, and ethnic background of the study population.
All the 18 studies included were briefly described regarding important characteristics, including 'type of physical exercise intervention, comparator, length of intervention, data collection, study population, country, setting, year(s) of the study, study design, type of economic evaluation'and key economic findings.
We thank Peter Hermanson and Robert Stupar for data collection for population 2. We also thank the two anonymous reviewers for their useful suggestions.
The differences may be due to differences in data collection methods, population age groups studied, and time.
This paper contributes to the literature on the feasibility and practicalities of accelerometer data collection in population studies, specifically in the context of rapid baseline data collection in the natural experimental setting.
Strengths of the study include the prospective data collection, general population setting, large number of participants and outcome events, high quality data on many factors (including medical history, vascular risk factors, lifestyle, and drug use), and validation of cardiovascular events.
The differences in the incidence rates may be due to variations in the definition of colic and of differences in study design, method of data collection and population size between different studies [ 6, 7].
T, N, M and stage grouping data collection in population-based cancer registries is feasible and desirable.
