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Analysis Approach for Assessing Textile Preferences on Net Use: Ghana 2022

Insecticide-treated nets are the cornerstone of malaria control efforts worldwide. Over 2 billion ITNs have been distributed to people at risk of malaria over the past two decades. While most ITNs are used for malaria prevention, some gaps in use remain. Anecdotal reports and qualitative observations have indicated that in some areas, households may prefer softer polyester ITNs to ITNs made of polyethylene, which can have a ‘harder’ feel.

As a result, National Malaria Control Programs have expressed a desire to procure only ITNs of a specific textile for upcoming mass distribution campaigns. While the Global Fund procurement system allows for these types of requests, they are unable to guarantee that nets of a particular textile will be available for a specific campaign, due to global supply chain issues, ITN production timelines, and other manufacturing variables.

The Global Fund and WHO have advised countries wishing to procure nets of a single textile that this decision must be justified with data that support a significant increase in overall ITN use for one textile over another.

This document aims to provide an analysis framework for use by National Malaria Control Programs and their partners wishing to demonstrate differential use of ITNs due to the textile of the net, in order to justify procurement of ITNs of a specific textile (polyester or polyethylene).

Summary of Analysis Approach

  1. Assess availability of data for analysis, including
    • completeness of brand information, in order to determine the textile
    • ITN use outcome variable, at the net level
    • covariates associated with ITN use, including region, socioeconomic status, rural/urban, month of the year (for seasonal variations), age of the net, and whether the household has sufficient or insufficient ITNs for their family size.
  2. Determine whether existing data is sufficient for assessing the impact of textile on ITN use
    • assess whether both textiles are sufficiently represented in the data
  3. If yes – proceed with analysis
    • assess associations between ITN use and textile, along with other covariates, first in a univariate model
    • and then in a multivariate model, ideally accounting for clustering within the household
    • if the programmatic differences in ITN use by textile are significant, and the multivariate model shows a significant association between ITN use and textile controlling for covariates, there may be a justification for procurement of a single textile.
  4. If data are not sufficient – recommendations for next steps
    • if data are incomplete -> collect complete data in the next survey
    • if one textile dominates the sample -> ensure a mix of textile types are distributed in the next campaign, then reassess

Analysis Approach

Assess availability and suitability of data for the analysis

  1. Download datasets for the most recent MIS or DHS or MICS from dhsprogram.com or mics.unicef.org

  2. If using an MIS or DHS, the ITN roster data are contained within the household file (files ending with HR). This file must be reshaped to long format, generating a dataset with one row for each net in the household. MICS datasets have a separate ITN file (TN).

  3. The outcome variable will be whether the ITN was used the previous night.

  4. Many household-level factors influence ITN use, and must be controlled for in the analysis. These variables are nearly always standard within MIS/DHS/MICS:

    • region

    • time of year (month of the survey)

    • urban/rural setting

    • socioeconomic status

    • age of the net

    • the number of nets and people within the household - frequently categorized as household owning

      • ‘too few’ ITNs,
      • ‘just right’ number of ITNs, or
      • ‘too many’ ITNs

Let us first review overall net use patterns across these covariates, to get a sense of what is happening in Ghana 2022.

Region

Time of year (month of the survey - which can vary by region)

Urban/Rural Status