_ANDR EE_<sup>_ ́_</sup> _DECEMBER - 2021_ _4_ by replacing a subset of expensive surveys with targeted predictions, and advance broader economic monitoring in data-poor regions.

The remainder of the paper has been structured as follows. The next section provides a brief overview of the type of price surveys that can be used to deploy the new monitoring capabilities and discusses some basic challenges encountered when trying to read inflation from the raw data. Section II details the imputation strategy and section III presents results. For those interested in analyzing the subnational price and inflation estimates further, all results for the 25 countries analyzed are available to be interactively explored.<sup>5</sup> Section IV provides concluding remarks and makes several recommendations for future data gathering.

# **I. Food Price Survey Data**

Subnational food prices have been surveyed in many countries for years by humanitarians to inform their country operations. Well-known data bases are those from the WFP, FEWS NET and the Food and Agricultural Organization (FAO).<sup>6</sup> The paper focuses on raw monthly data from the WFP, but parts of the discussion, and particularly the methods developed here, could apply to similar data sets.<sup>7</sup> The paper gathered all end-of-August data available from the WFP Vulnerability Analysis and Mapping (VAM) unit as of September 21, 2021. The WFP data reports prices as measured in different market locations throughout each country. Price quotes are supplied by WFP country and regional offices, and local partners including the FAO. In total, the data base covers over 2,000 markets across 99 countries, and reports monthly data on the prices of goods that vary by country and market. Price monitoring dates back to early/mid 2000s in most countries, while in few countries monitoring began already in the 1990s.

The number of markets varies strongly by country, ranging from 1 to well over a 100. The methods developed by the paper are particularly interesting when there are multiple markets, as otherwise, official CPI data may provide sufficient, if not better, insight. The goods for which prices are collected, and the manner in which these prices are measured, in turn vary widely across markets and may change over time. For example, prices of some goods are collected at the retail level in some markets, while for others they are collected at the wholesale level and include discounts typical for large purchases. Generally, prices are measured in nominal local currency per unit of commodity (e.g. Shillings per 10 kg of maize), but in some countries USD quotes on selected goods may exist alongside

> 5With the publication of the paper, new monthly food price estimates by product and market using the methods and data described in this paper, will be made available on the World Bank Microdata Library. They can be viewed and downloaded at https://doi.org/10.48529/2ZH0-JF55 or, currently, https://microdata.worldbank.org/index.php/catalog/4218. The citation is Andr ́ee (2021).

> 6There are also country-specific data gathered by FSNAU (Somalia) and CLiMIS (South Sudan). More recently, the International Food Policy Research Institute has piloted gathering high frequency prices in several countries.

> 7For instance, estimates have also been developed for Papua New Guinea in collaboration with IFPRI in a separate pilot project. Results can be requested from the author.