As these approaches evolve independently, they portray an unprecedented opportunity to sidestep the challenges associated with traditional enumerator-based price data surveillance, including extensive temporal lags (sometimes >5years gap), coarse spatial resolution, and poor market segment coverage (Zeug, et al., 2017). Further, as the data systems mature, they can complement enumerator-led efforts by enriching national data systems with high-frequency price monitoring. However, for the data outputs to be considered useful, it is imperative to validate against standard enumerator-submitted data across market locations and over time. Due to the nascence of these innovative data approaches and sources, it is uncertain if these alternative estimates of commodity prices are credible reflections of market signals and actual price levels. Both approaches are characterized by inherent limitations. For instance, the crowdsourcing approach can arguably be influenced by the vagaries of independent volunteers who may submit spurious or outdated price data at will, defying the inbuilt controls to enforce the integrity of the data collection system (Solano-Hermosilla, et al., 2022; Arbia, et al., 2023). Similarly, model-based price estimates from AI algorithms can be subject to various accuracy issues and uncertainties due to parameterization and bias (Aldoseri, et al., 2023; Andrée, 2021a). Therefore, independent ground-truthing against enumerator-led data, and evidencing [dis]agreement between these data sources, is imperative to guide further innovation and engagement of stakeholders to advance real-time assessment of food price changes, affordability, and food security.

# _Study Area_

We focused this comparative study on three (3) major states in the core northern region of Nigeria (Figure 1), where the geographical and time-range coverage of the World Bank’s RTP (henceforth, AI-estimated) food prices overlap with crowdsourced price submissions. With a combined population of 30.5 million, the focal states account for 15% of the national population (UNFPA, 2023) and approximately 6.5% of the national GDP (BudgIT, 2022). Characterized by low literacy and historically high levels of insecurity, this region has faced lingering threats of food insecurity and the expedient need for relevant interventions provides context for alternative high-frequency surveillance of food commodity prices and timely insights into overall market conditions. In the period preceding the data crowdsourcing efforts, this region of the country was under severe warning for insecurity due to terrorism, armed banditry, and religious crisis. Historically, agricultural production has played a major role in the economy of the three states, with cultivation of major staple crops such as maize, cowpea, soybeans, and local rice. The geographical coverage extends through the Northern and Southern Guinea savanna agroecological zone; therefore, the major sowing and harvesting season occurs between June and October annually, and most grain crops are cultivated under rain-fed and irrigated conditions. The major markets are usually active throughout the year, varying in size, and typically featuring vendors from wholesalers to retailers. There are smaller markets that are periodically open (such as village markets, proximate to farm gates), while the major cities feature small and mid-sized local retailers (including kiosks, shops, supermarkets, etc.). Due to the presence of active trade routes within the region, people (buyers and sellers) and goods move between markets, while vendors can own multiple stores within and across markets, potentially influencing spatial price transfer.

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