I switched identifiers partway through this.
For "id" read "country", throughout.
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Nick Cox
> Sent: 25 March 2004 10:24
> To: [email protected]
> Subject: st: RE: count non-missing elements in a series
>
>
> You don't give a very clear idea
> of your data structure. I guess that you
> have panel data, something like
>
> . tsset country year
>
> and a series of variables for different
> industries, say
>
> industry1-industry10
>
> What you want in question 1 can be got in
> various ways. Here is one:
>
> The first value for each panel is 1 if
> the investment value is not missing and 0 otherwise:
>
> . by id : gen nrun = !mi(industry1) if _n == 1
>
> Subsequent values are always 0 if the investment
> value is missing and 1 greater than the previous
> otherwise.
>
> . by id : replace nrun =
> cond(mi(industry1), 0, nrun[_n-1] + 1) if _n > 1
>
> Another way of doing it is to use -tsspell- from SSC.
> Install that by
>
> . ssc inst tsspell
>
> Then for say -industry1- the definition of a spell is
> just a sequence of non-missing values of -industry1-.
>
> . tsspell, c(industry1 < .)
>
> The variable _seq created by -tsspell- is what
> you want. Spells automatically are determined
> separately by panel.
>
> If different industries have different patterns
> of missing values, you would need something
> more like this:
>
> forval i = 1/10 {
> tsspell, c(industry`i' < .) spell(_spell`i')
> seq(_seq`i') end(_end`i')
> }
>
> After which you might want to -drop- some of the created variables.
>
> Nick
> [email protected]
>
> Oleksandr Shepotylo
> >
> > I am using perpetual inventory method to calculate
> > capital stock but my
> > dataset has a lot of missing data on investment. I have two
> questions:
> >
> > 1. For any given country and industry, I want to create
> > an index that
> > will tell me how many
> > non-missing numbers in a row I have prior to any year t.
> > For example, I have investment data for country i and
> > industry j starting
> > from 1965 to 1975 then missing in 1976-1977 and continuing in
> > 1978-2001. The
> > index should start from 1 in 1965 till 11 in 1975. then it
> equals 0 in
> > 1976-1977 and starts from 1 again in 1978.
> >
> > 2. Less important, but still interesting. How to impute
> > missing data if
> > the gap- like in previous example- is less or equal to 2?
> > Imputation can be
> > based on average growth in capital stock for last 3 years.
>
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