Against this background, we present new findings from a large-scale randomized survey experiment conducted in Malawi to document the relative accuracy of recall-based approaches to time use survey data collection. <mark>The experiment assigns random samples of households, and adult men and women within, to one of two treatment arms on time use measurement: a traditional 24-hour recall time use diary; and a self-administered smartphone-based pictorial time diary, known as the</mark> _<mark>TimeTracker</mark>_ <mark>app.</mark> While real-time data collection on time use has been explored in other surveys in higher-income settings (Gershuny et al., 2020), our study is the largest one implemented to date in a low-income country, extending a nascent evidence base regarding the feasibility and utility of smartphone-based time use data collection - previously only available for Zambia, though for a significantly smaller, rural-only sample (Daum et al., 2018, 2019). Beyond the methodological contributions of our work, we reveal new, policy-relevant insights regarding intra-day variation and simultaneity in time use.

The analysis compares men’s and women’s self-reported time allocation across two survey treatment arms, over an 11-day reporting period, to provide a disaggregated, comparative analysis of real-time and recallbased survey approaches over shorter (24-hour) and longer (7-day) recall periods:

- (1) In the first treatment arm, one adult man and adult woman (aged 15-64) in each household received an Android smartphone-based pictorial time use diary app called _TimeTracker_<sup>4</sup> to selfreport their time use across a set of activities on a continuous, real-time basis over the period. The app was developed specifically for time use data collection in low-literacy settings (Daum et al., 2018) where respondents do not necessarily have clock-based concepts of time and no prior experience with smartphones.

- (2) In the second treatment arm, one adult man and adult woman in each household received a traditional, recall-based 24-hour diary interview on three different days during the reporting period, where interviewers asked respondents to recall their time allocation over the last 24 hours and coded the reported activities into 15-minute intervals based on the respondent’s narrative, with up to two simultaneous activities that can be recorded for each 15-minute interval.  Reporting in the recall diary arm covered the same activity set as in the smartphone arm.

- (3) Finally, at the end of the reporting period, respondents in both treatment arms received a stylized interview-based 7-day recall module covering a subset of activities in the smartphone/recall diary approaches. The 7-day module follows a structure commonly implemented in labor force surveys or socioeconomic household surveys (Seymour et al., 2020), and allows us to investigate how the same groups varied their responses over recall periods of different lengths.

Our findings span three key areas, with important contributions to the literature. First, on participation and time across different activities, we show that the smartphone and recall arms provide very different perspectives, along with an interesting dichotomy in activity sets highlighted across the two arms. Recall, for example, leads to an underreporting of participation in employment and unpaid work, including a lower

> 4 _Time Tracke_ r was originally developed by the University of Hohenheim and the Institute for Applied Science (University of Media, Stuttgart) (Daum et al., 2018, 2019) and enhanced for this study with World Bank LSMS support. While the app is not yet publicly available, there is a plan is to release it for public use.

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