toby dunn wrote: > This is one way: > > Data Need ; > Set Have ; > By ID Visit ; > Retain NewX1 NewX2 NewX3 ; > > If First.Visit Then Do ; > NewX1 = X1 ; > NewX2 = X2 ; > NewX3 = X3 ; > End ; > Else Do ; > NewX1 = NewX1 * X1 ; > NewX2 = NewX2 * X2 ; > NewX3 = NewX3 * X3 ; > End ; > > If Last.Visit Then Output ; > > Run ; > > > Personally Id restructure your data and the problem becomes even > easier to solve:

And if SAS SQL had a new function named PROD, things would be even easier

Proc SQL; create table summary as select id, visit, name, PROD(value) as value from HAVE_VECTOR group by id, visit ; quit;

-- Richard A. DeVenezia http://www.devenezia.com/