The FAQ advises
"Say what command(s) you are using. If they are not part of official
Stata, say where they come from: the STB/SJ, SSC, or other archives."
In this case, some detective work reveals that -prsnperd- is
a user-written command by Alexis Dinno, at the Harvard School
of Public Health when the program was written. I do not know
whether Alexis is a member of Statalist, but in any event the
program author will be the best source of support given
problems. It is possible, naturally, that somebody else has
used the program and/or is prepared to look at the code and
so will be able to comment, more usefully than to point out
that a spelling mistake is embedded in the code, which is
all I can identify from reading this.
Nick
[email protected]
Jinseok Kim
> I created a person-period data set using prsnperd command to conduct a
> discrete time hazard model and found a potential error in the data set
> created. Here's the syntax I used:
>
> . prsnperd childid minccage1 censored, t(72)
> No variation in event occurence for period 22!
> No variation in event occurence for period 32!
> No variation in event occurence for period 66!
> No variation in event occurence for period 68!
> No variation in event occurence for period 72!
>
> If I understand correctly, _period variable created by prsnperd should
> have values ranging from 1 to 72 because minccage1, my length-to-event
> variable in the model, has a maximum value of 72. And here's what I
> found strange:
>
> . tab _period if _period>72&_period<100, miss
>
> _period | Freq. Percent Cum.
> ------------+-----------------------------------
> 73 | 12 3.86 3.86
> 74 | 12 3.86 7.72
> 75 | 12 3.86 11.58
> 76 | 12 3.86 15.43
> 77 | 12 3.86 19.29
> 78 | 12 3.86 23.15
> 79 | 12 3.86 27.01
> 80 | 12 3.86 30.87
> 81 | 12 3.86 34.73
> 82 | 12 3.86 38.59
>
> *** I intentionally cut here to save the space...*******
>
> 94 | 11 3.54 82.32
> 95 | 11 3.54 85.85
> 96 | 11 3.54 89.39
> 97 | 11 3.54 92.93
> 98 | 11 3.54 96.46
> 99 | 11 3.54 100.00
> ------------+-----------------------------------
> Total | 311 100.00
>
> . tab _period if _period>1000, miss
>
> _period | Freq. Percent Cum.
> ------------+-----------------------------------
> 1001 | 1 0.20 0.20
> 1002 | 1 0.20 0.40
> 1003 | 1 0.20 0.60
> 1004 | 1 0.20 0.81
> 1005 | 1 0.20 1.01
> 1006 | 1 0.20 1.21
> 1007 | 1 0.20 1.41
> 1008 | 1 0.20 1.61
> 1009 | 1 0.20 1.81
> 1010 | 1 0.20 2.02
> 1011 | 1 0.20 2.22
> 1012 | 1 0.20 2.42
>
> I like to hear from you all regarding whether I missed something while
> I use it, or it is a known glitch. Thanks.
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