The Transition into Adulthood Supplement (TAS) has collected information about college major (field of study) in all waves (2005-present). Because college majors can be unique and therefore potentially identifying, detailed information about college major is made available under restricted contract. The file contains 2,595 records and 11 variables. The first five variables in each file are the keys needed to merge with the Public Release version of the corresponding PSID Cross-year Individual/Family file and/or the corresponding TAS Interview File.

As of TAS-2019 we have coded college major using the new code frame provided by the National Center for Education Statistics (NCES): Classification of Instructional Programs (CIP 2010 frame). Given the granularity of the code frame, we have provided two variables for each report of college major.
  The first variable is the first 2 digits of the CIP which is the main category (e.g., 01=Agriculture, Agricultural Operations, and Related Sciences). The 2-digit version of this variable is publicly available. The second corresponding variable for each report of college major is the full CIP code, in the format XX.XXXX. This variable is suppressed and only available for use under a restricted data use contract. Users should note that these college major variables have character values preserving the leading zeros to match the CIP 2010 frame. The TAS-2019 College Major codebook describes the restricted variables.