lpoly for panel data

[muly san]

How can I obtain polynomial trend for panel data (for each group separately)?
Thanks

[Joseph Coveney]

Maybe by using an if expression? Assuming based upon your title that you want to use lpoly to "obtain polynomial trend", then something like

quietly levelsof group, local(groups)
pause on
foreach group of local groups {
    lpoly response time if group == `group' // assumes group is numeric, use "`group'" otherwise
    pause
}