graphing a change with xtline

[Julia Raciniewska]

Hello,

I have issues with the command to generate a graph which will show a change of my variable over time.
I have panel data for 10 industries between 2006-2017. I would like to graph a change in their investment in computer hardware: although each industry differs in investment at the base year (2006), I would like to assume that all 10 industries start at 0 change, and then show how their investment expenditure has changed over time.
What I have done so far is:
xtset industry time
gen changehardware = (hardware - L1.hardware)/ L1.hardware
xtlinechangehardware, overlay

However, this way there is a difference between them even at year 2006. Could someone please help?

[Andrew Musau]

The initial value will be missing as you are using the lag operator. You may want something like

bys industry (time): gen changehardware =cond (_n==1, 0, (hardware - L1.hardware)/ L1.hardware)