David McRitchie, thanks for your help here. re variables (inputs and
outputs) i was no so much talking about macros but more in the
generic. for example some would say a graph is an 'output' of some
pupil data say. but imagine i had some data in column A and in columnB
converted this into a percentage - could the percentage(s) be
considered an 'output' also? thanks for all your help.