This document discusses how to merge household and individual files from two rounds of a survey, the India Human Development Survey (IHDS). It provides steps to link households and individuals surveyed in both rounds using a linking file, and explains concepts like replacement households, split households, and attrition. The key steps are: 1) Linking the round 2 data to the linking file to get round 1 IDs, 2) Merging this new round 2 file with the round 1 file. The merged files will be a superset containing individuals surveyed in one or both rounds.