The survey approach: independent or combined with another

Information on micronutrient status and on the implementation of relevant interventions may be collected either through an independent survey or as a component of another population-based survey. There are many other surveys to which a micronutrient module could be added. It is important to assess in the earliest stages of planning whether other surveys that cover the same population group or geographic area are being planned. If so, stakeholders should discuss whether it would be possible to expand the scope of the other survey(s) to include a micronutrient module and share resources. Some advantages and disadvantages of incorporating a micronutrient component into or linking with another planned survey are presented in Box 4.3.

Box 4.3. Advantages and disadvantages of incorporating a micronutrient component into another planned survey

Advantages:

  • A sampling frame may have already been developed by the lead agency of the other survey.
    • If the sample size (for the same population group of interest) for the planned survey is larger than that needed for the micronutrient component, a subsample of clusters, households, or participants could be systematically selected for the micronutrient component.
  • There may be access to additional data variables collected through the other survey that would increase the scope for subgroup analyses in relation to micronutrients and micronutrient interventions.
  • Skilled survey staff would already have been identified and trained.
    • It may be necessary to complement the other survey team with additional enumeration staff, laboratory staff and a technical field and logistics team. These staff would need to be trained in the specifics of specimen collection and transport required for the micronutrient module.
  • Logistics support would already be available.
    • Additional logistical requirements may need to be determined and put in place, for example, cold chain facilities.
  • The potential burden of conducting more than one large-scale survey in the same country during the same time frame will be avoided.

Disadvantages:

  • The survey may not include a sufficient number of households per cluster to obtain stable estimates for some population groups, for example young children.
  • Incorporating a micronutrient component may require additional time for data collection in the field compared to the surveys being conducted independently.
  • There may be complications in ensuring that the objectives of both surveys are met.
  • There may be lower participation rate or higher rate of incomplete questionnaires if the questionnaire becomes significantly longer as a result of combining two surveys.

To determine whether or not to integrate a micronutrient module with another survey, three important questions should be considered:

  1. Will the government and the organizers of the other survey agree to incorporate the micronutrient module?
  2. Will it be possible to collect data from a representative and large enough sample in the population groups of interest in the desired geographic areas to meet the objectives of the micronutrient survey? (Sample size is discussed in Module 5, Sample size.)
  3. Will the integration save costs and reduce the burden on participants?

Gaining agreement and commitment from the team implementing another survey to incorporate a micronutrient module may be a significant challenge. There may be many concerns from the organizers, including that the timelines and survey design requirements might not align or that the added complication of collecting biological specimens might compromise the main survey.

If integrating into another planned survey is not an option, it may still be possible to use the sampling frame from a previously conducted survey. The advantage to this is that the first-stage sampling may have been performed and the maps and information to identify households and subjects may already be developed and available. One example of an integrated survey is the 2015-16 Malawi Micronutrient Survey, which was carried out jointly with the 2015-16 Malawi Demographic and Health Survey. 1

  1. National Statistical Office, Community Health Sciences Unit [Malawi], US Centers for Disease Control and Prevention (CDC), Emory University. Malawi Micronutrient Survey 2015-16. Atlanta: US Centers for Disease Control and Prevention; 2017 (https://dhsprogram.com/pubs/pdf/FR319/FR319.m.final.pdf, accessed 15 June 2020). 

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