When the Rodgers/Rowe research team first developed NLSY-Children kinship links in the early 1990s (with programming support from Kim May and Chengchang Li), two other research teams also programmed their own kinship links at approximately the same time (one led by Edwin van den Oord in The Netherlands, the other led by Nazli Baydar in the U.S. and Turkey). Those were independent developments, but we eventually collaborated extensively with van den Oord, and compared kinship links with Baydar. As we have continued to improve and expand the NLSY kinship links through the years, we have provided those to many research teams around the world.
There have been three primary mechanisms by which researchers have requested kinship links:
For the first several cycles of kinship links - through the release of the revised NLSYC/YA links in 2004 (developed by Joe Rodgers, Amber Johnson, and David Bard) - we have only circulated the kinship links themselves, and have considered the SAS coding associated with the linking algorithm to be proprietary.
After the most recent release of the NLSY79 and NLSYC/YA kinship links in November, 2013 (developed by Will Beasley, Kelly Meredith, David Bard, and Joe Rodgers), we have provided the algorithm online as open-source code, and users are welcome to adapt it to their own purposes.
Starting in 2011, we have also provided a User-Service function (funded both by the most recent NIH grant, and also the University of Oklahoma and Vanderbilt University). Graduate students in quantitative psychology - Kelly Meredith, Mike Hunter, and Mason Garrison - who have expertise in using the kinship links are available for consult on both design and software issues associated with fitting biometrical and other sibling models using the kinship links.
Along with the most recent release of the two sets of kinship links, we also developed a set of vignettes (programmed by Will Beasley and Mike Hunter) that provide instructions and code to facilitate researchers in using the NLSY kinship links. Both R-based and SAS vignettes are available online through CRAN.
In the near future, we expect the kinship links to also be available as a link off of the BLS/CHRR website, to further facilitate researchers who wish to use the kinship links. The User Service function will continue through at least 2015, and potentially longer depending on future institutional and grant support.