search
for
 About Bioline  All Journals  Testimonials  Membership  News


The Journal of Health, Population and Nutrition
icddr,b
ISSN: 1606-0997
EISSN: 1606-0997
Vol. 23, No. 1, 2005, pp. 66-73
Bioline Code: hn05008
Full paper language: English
Document type: Research Article
Document available free of charge

The Journal of Health, Population and Nutrition, Vol. 23, No. 1, 2005, pp. 66-73

 en Intra-class Correlation Estimates for Assessment of Vitamin A Intake in Children
Agarwal, Girdhar G.; Awasthi, Shally & Walter, Stephen D.

Abstract

In many community-based surveys, multi-level sampling is inherent in the design. In the design of these studies, especially to calculate the appropriate sample size, investigators need good estimates of intra-class correlation coefficient (ICC), along with the cluster size, to adjust for variation inflation due to clustering at each level. The present study used data on the assessment of clinical vitamin A deficiency and intake of vitamin A-rich food in children in a district in India. For the survey, 16 households were sampled from 200 villages nested within eight randomly-selected blocks of the district. ICCs and components of variances were estimated from a three-level hierarchical random effects analysis of variance model. Estimates of ICCs and variance components were obtained at village and block levels. Between-cluster variation was evident at each level of clustering. In these estimates, ICCs were inversely related to cluster size, but the design effect could be substantial for large clusters. At the block level, most ICC estimates were below 0.07. At the village level, many ICC estimates ranged from 0.014 to 0.45. These estimates may provide useful information for the design of epidemiological studies in which the sampled (or allocated) units range in size from households to large administrative zones.

Keywords
Vitamin A; Vitamin A deficiency; Sample size; Epidemiology: Child; India

 
© Copyright 2005 - ICDDR,B: Centre for Health and Population Research
Alternative site location: http://www.jhpn.net

Home Faq Resources Email Bioline
© Bioline International, 1989 - 2024, Site last up-dated on 01-Sep-2022.
Site created and maintained by the Reference Center on Environmental Information, CRIA, Brazil
System hosted by the Google Cloud Platform, GCP, Brazil