NSDP Methodology

Nominal NSDP Data

Nominal net state domestic product (NSDP) data was primarily sourced from the Reserve Bank of India (RBI)'s Handbook of Statistics on the Indian Economy, 2023-24. In this report, the RBI only published data from FY 1993-94 onwards, so I obtained FY 1980-81 to FY 1992-93 data from the RBI's Handbook of Statistics on the Indian Economy, 2008-09. Furthermore, I was unable to easily access NSDP data from the 1960s and 1970s directly from the government, so I procured these figures from Indiastat, an Indian data analytics company that obtained historical NSDP data from the Government of India's Central Statistical Office. NSDP is used as the measure of economic output because gross state domestic product (GSDP) figures do not appear to be available across as long a historical time frame.

A couple other notes are in order. First, for some reason the RBI Indian Economy handbooks did not contain data on Telangana for FY 2004-05 to FY 2011-12, so I procured these numbers from the RBI's Handbook of Statistics on Indian States 2022-23. Second, the RBI did not publish FY 2023-24 data for some states (presumably because these states were late in reporting). When possible, I sought out other sources to obtain figures for these states. Gujarat and Goa, in particular, published GSDP estimates but appear to not have yet released NSDP estimates. Hence, I calculated NSDP estimates under the rough assumption that NSDP grew at the same rate as GSDP. For some other states/UTs, primarily located in the Northeast, I was unable to find GSDP or NSDP estimates. I plan on updating the 2023-24 data with official figures for these states in the future. 

Third, the Indian government has periodically updated their calculations of NSDP, and so sometimes different estimates of nominal NSDP exist for the same year. In those cases, I averaged the estimates between the two series, unless the new series newly separated out states that had undergone a split (such as Bihar and Jharkhand), in which case I utilized the estimate from the new series for that year. 

Fourth, even in the official NSDP series, some states have missing data for some (though far from most) years. For these missing years, I inputed their values by linearly interpolating the logarithm of NSDP. For a handful of relatively small states with missing data in the 1960s and 1970s, I extrapolated values using pre-1991 log NSDP. 

Population Data

The Government of India typically conducts censuses every decade and has published statewide figures on population from 1951 to 2011. As of writing, India has not conducted a census since 2011, but the government published population estimates for 2023 using vital statistics and other data in a report. Using census data and these estimates, I interpolated values between census years and between 2011 and 2023 using a cubic spline. I recognize that there may be superior means of interpolating values or that it may be possible to collect the government's population estimates for every year, but I hope this was a time-efficient means of computing rough estimates.

Price Data

Annual consumer price index data for India were obtained from the Federal Reserve Bank of St. Louis.

Regions

The regions in the dataset are defined as follows:

Additional Datasets

Population estimates