Methodological Document: the New Consumer Price Index

This IHSI methodological document explains Haiti's rebased consumer price index with base 100 in 2017-2018. It sets out the reasons for rebuilding the index, reviews CPI concepts, gives a history of Haiti's CPI, presents the new 2017-2018 CPI, explains its spatial coverage, basket construction, weights, price collection and calculation system, and describes how the new series is linked to the previous CPI base 100 in August 2004. It defines operational concepts such as consumption divisions, expenditure groups, expenditure posts, varieties, observations, consumption basket, elementary index, upper-level index, short-term index and weighting.

The document notes a key methodological change: elementary price aggregation now follows international recommendations by using the geometric mean, unlike the previous index's arithmetic mean. It also includes comparisons between the new index and the August 2004 index at the overall, basket, weight and trend levels. Large annex tables present CPI values by expenditure post for the whole country, as well as local-product and imported-product indices, from January 2010 through December 2018. The document is the reference for interpreting Haitian CPI and inflation across the series break and for understanding the representativeness, reliability, coverage and publication-lag improvements expected from the new index.