Hi Jan. I hope you are OK. I'm stuck in the same problem. Did you find an answer for this question? Thanks in advance, Edgar -- View this message in context: http://r.789695.n4.nabble.com/Malmquist-Luenberger-Productivity-Index-programmed-in-R-tp4643842p4663436.html Sent from the R help mailing list archive at Nabble.com.