# **_Improving migration measurement in household surveys_**

The first and most straightforward issues when using household surveys to study migration are the limited amount of adequate migration information that is generally collected as well as the lack of consistency in survey-based measures of migration. As already discussed, this is in part due to the absence of standardized, internationally recognized definitions of different migrant typologies, including the new category of “climate migrants”. ‘Rare event’ issues aside, this paucity of information translates into a limited ability of household surveys to capture (present and past) migrants in the original household sample even when they actually exist. To tackle these challenges, we recommend the following improvements:

- Starting with the few available official definitions and looking at best practices in the design and collection of migration data, efforts should be devoted to developing **state-of-the-art migration questions and modules** that can be embedded within multi-topic household surveys with sufficient consistency across space and time.

- As migration is not a unimodal concept, it is important that the information collected through the survey instruments allows for **differentiating categories of migrants** (permanent, temporary, seasonal, circular, return, etc.) **and types of migration** (rural, urban, internal, international, economic/voluntary, forced, etc.) with the highest possible precision and, at the same time, in an efficient way (i.e., without overburdening the questionnaire).<sup>28</sup> This implies testing and validating alternative approaches for collecting key migration information such as the length and frequency of the migration episodes, the geography of the migration moves, and the motives of migration.<sup>29</sup>

- Special attention must be devoted to identifying innovative methods for reducing well-known issues related to the **use of proxy respondents and recall bias** . The adoption of mixed-mode survey designs leveraging the use of new technologies, such as mobile phones and widely used free messaging apps or social media information (e.g., Facebook data), is a promising avenue to explore in the context of international migration, as demonstrated by recent studies (Ndashimye et al., 2022). Combining remote data collections and big data with face-to-face household surveys can be an effective way to improve the quality of migration information as it allows for direct reporting of the subject of interest (i.e., the migrant), rather than relying on a proxy respondent, and for recording migration-related events at a higher frequency (e.g., in between panel waves or even survey visits) while also minimizing potential recall bias.

> 28 It is important to note that the possibility of clearly defining different categories of migrants matters as well for the ‘rare event’ problem as the rarity of the event also depends upon the definition adopted and the type of migrant being studied given that certain types of migration might not be as infrequent in the context of a household survey (De Brauw and Carletto, 2012).

> 29 For example, Gillespie et al. (2021) discuss the main methodological issues in the measurement of migration motives focusing on the use of open-ended questions and the strengths and weaknesses of this method.

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