Impact of methodological "shortcuts" in conducting public health surveys: Results from a vaccination coverage survey

Elizabeth T Luman,Mariana Sablan,Mary M Mccauley,Kate M Shaw,Shannon Stokley

doi:10.1186/1471-2458-8-99

Abstract

BackgroundLack of methodological rigor can cause survey error, leading to biased results and suboptimal public health response. This study focused on the potential impact of 3 methodological "shortcuts" pertaining to field surveys: relying on a single source for critical data, failing to repeatedly visit households to improve response rates, and excluding remote areas.MethodsIn a vaccination coverage survey of young children conducted in the Commonwealth of the Northern Mariana Islands in July 2005, 3 sources of vaccination information were used, multiple follow-up visits were made, and all inhabited areas were included in the sampling frame. Results are calculated with and without these strategies.ResultsMost children had at least 2 sources of data; vaccination coverage estimated from any single source was substantially lower than from all sources combined. Eligibility was ascertained for 79% of households after the initial visit and for 94% of households after follow-up visits; vaccination coverage rates were similar with and without follow-up. Coverage among children on remote islands differed substantially from that of their counterparts on the main island indicating a programmatic need for locality-specific information; excluding remote islands from the survey would have had little effect on overall estimates due to small populations and divergent results.ConclusionStrategies to reduce sources of survey error should be maximized in public health surveys. The impact of the 3 strategies illustrated here will vary depending on the primary outcomes of interest and local situations. Survey limitations such as potential for error should be well-documented, and the likely direction and magnitude of bias should be considered.

Highlights

Lack of methodological rigor can cause survey error, leading to biased results and suboptimal public health response
In smaller field surveys worldwide, limited time and financial resources, poor accessibility of households, and lack of available transportation and staff may limit the extent to which these strategies can be implemented. While these surveys often provide practical information used as management tools for evaluating and targeting health services, in extreme cases survey error could result in severe bias, proliferation of misinformation, and suboptimal public health response
Among children aged one year (12–23 months), we evaluated receipt of vaccines recommended by age 12 months: three doses of diphtheria-pertussis-tetanus vaccine (DPT), three doses of inactivated poliovirus vaccine (IPV), two doses of hepatitis B vaccine, and three doses of Haemophilus influenzae type b vaccine (Hib)

Summary

Introduction

Lack of methodological rigor can cause survey error, leading to biased results and suboptimal public health response. In smaller field surveys worldwide, limited time and financial resources, poor accessibility of households, and lack of available transportation and staff may limit the extent to which these strategies can be implemented. While these surveys often provide practical information used as management tools for evaluating and targeting health services, in extreme cases survey error could result in severe bias, proliferation of misinformation, and suboptimal public health response. In this study we examine additional sources of survey error and the potential impact of three "shortcuts" that are sometimes taken when conducting household surveys:

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