1rd1klvz.pdf is a paper on description of death data:
"Type of OASDI Benefit and Year of Death based on an Exact Match to
Social Security Administration Benefit Records, 1990 and 1991 Panels 
of the Survey of Income and Program Participation (SIPP):
Description of the Development of the Data for Public Release and a
Preliminary Evaluation of Data Quality 
by Denton R. Vaughan