I can supplement my previous query with a report based on my experiments, which may be an error or a feature. A skeleton example is as follows: function xpanel(x) genr dtest1=$datatype print dtest1 # Should print 3.000 for panel data genr xunit=$unit genr time setobs 1 1 --cross-section genr dtest2=$datatype print dtest2 # Should print 1.000 as data is now cross-section smpl ok(x) --restrict ... return series y setobs xunit time --panel-vars genr dtest3=$datatype print dtest3 # Should print 3.000 for panel data end function Now call xpanel using a dataset that has been defined as a panel dataset: genr test1=$datatype print test1 # Should print 3.000 for panel data series y = xpanel(x) genr test2=$datatype print test2 # Should print 3.000 for panel data but actually the result is 1.000 What is happening is that it is possible to redefine the datatype from panel to cross-section within the function and operate on the (sampled) cross-section data. Further, the setobs command at the end appears to allow you to go back to the original panel structure. However, that does not get stick when you goes back to the original calling routine and you are left with cross-section data at the higher level . Gordon