In reply to Mark Keintz.

Mark, thank you for your comment. I totally agree with you that for different scenarios different solutions may be warranted. We are not talking "one size fits all" solution here; it is always a good idea to have an arsenal of diverse tools to choose from. I particularly target this hop() solution to clinical trials processing, where programmers deal with relatively small data tables and very tight programming deadlines. Plus, if suggested here hop() function (not my surrogate %hop() macro) is implemented in SAS, it might be fulfilled by different algorithms and means than point= option and be much more efficient for large data processing.