st: Panel Differences

["Alexander Nervedi" <alexnerdy@hotmail.com>]

Hi,

I have data on a panle of 10 kids for 10 years observed approximately every 
3 weeks. It kind of looks like as below.

For each child I'd like to get the difference in the date of interviews. 
Simple things like

gen diff = interview - L1.interview fail me since the tsset command assumes 
that the day preceeding the current interview date (i,t), is a (i, t-1) 
where the t-1 is not specific to the i but for anyonein the data set. 
Consequently interview(i, t-1) may well be missing.

I was wondering what the simplest way would be to get the average distance 
between interview dates for each of these 10 kids over the 10 year period.

thanks.

alex


ID   year  interview
1      1      10
1      1      47
...
1      1    365
1      2      31
1      2      62
...
1      2    340
...
1     10    342
2      1     10

...

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