Definition
NDVI consists of a set of 72 variables. These variables report the maximum normalized difference vegetation index (NDVI) value within a 10 kilometer circular buffer around each DHS cluster for the 60 individual months prior to the survey start date, the month of the survey start date, and the 11 individual months following the survey start date. NDVI is a numeric, normalized index that measures live greenness in an area and can be used as a proxy for vegetation. NDVI values range from 0 to 1.
By adding NDVI to your data cart, you are in effect adding 72 separate variables:
The 60 individual months prior to the survey start date, denoted by the number of months prior to the survey start date (e.g., NDVI_01 is the maximum NDVI in the month before the survey start date; NDVI_60 is the maximum NDVI in the 60th month before the survey start date).
The month of the survey start date (NDVI_00)
The 11 individual months following the month of the survey start date, denoted by the number of months following the month of the survey start date (e.g., NDVI_A01 is the maximum NDVI in the month following the month of the survey start date).
Please see the User Note on Using IPUMS-DHS Contextual Variables: NDVI [URL omitted from DDI.] for the data source, methodology, and more detailed information about these variables.
