st: Re: Fill Missing values at the End

[Nick Cox <njcoxstata@gmail.com>]

This appears to be the third posting of this question. (In fact, as I
wrote this, yet another posting appeared.)

Please see the Statalist FAQ at

http://www.stata.com/support/faqs/resources/statalist-faq/#noanswer

to see that is one more than allowed.

You also sent me personal mail.

Again, not to do that is explained in the FAQ

http://www.stata.com/support/faqs/resources/statalist-faq/#private

Repeating a question (or minor variants of it) again and again is
_not_ likely to get more attention for your question than you would
otherwise get. In fact, it draws attention to yourself as someone who
(apparently) didn't read the FAQ carefully and/or doesn't respect the
list. No one is obliged to answer anything on Statalist. If you want a
tame consultant, hire one and pay accordingly.

In this case David Ashcraft posted a suggestion

http://www.stata.com/statalist/archive/2014-01/msg00206.html

to which you replied

http://www.stata.com/statalist/archive/2014-01/msg00207.html

I don't understand the reply, but I don't think it explained why
David's suggestion didn't work.

In any case, your recipe is to use the last known value and the value
4 years before that and extrapolate forward, or to use the first known
value and the value 4 years after that and extrapolate backward. You
don't need new code to do that. It is an application of -ipolate-.

1. Clone your variable.

2. Replace the 4th, 3rd, 2nd last known values with missing.

3. Replace the 2nd, 3rd, 4th known values with missing.

4. Use -ipolate-.

gen y2 = y
gen ismissing = missing(y)
bysort ismissing name (year) : replace y2 = . if inlist(_n, 2, 3, 4,
_N-3, _N-2, _N-1)
drop ismissing
bysort name (year): ipolate y2 year, gen(y3) epolate

You want to use

gen y_new = cond(missing(y), y3, y)

I addressed the restriction only to apply when there are 5 or fewer
values missing in an earlier reply, so I won't repeat that here.

http://www.stata.com/statalist/archive/2014-01/msg00187.html

Nick
njcoxstata@gmail.com


On 8 January 2014 15:05, Sadia Khalid <sadiakhalid234@gmail.com> wrote:

> I have working on Panel data. For some of the individuals end values
> are missing. I have to fill these values by first calculating the
> growth of the known five values.
>
> Like for the individual Aqueela values for the year 1996 – 2000 are
> missing. I will first calculate the growth rate of values from
> 1991-1995. the formula for calculating the growth rate is
> =((41.6/39.9)^(1/(5-1))-1). The growth rate is 1.05%.
> now the value in 1996 = value in 1995*(1+growth rate).
>
> And value in 1997= value in 1996 * (1+growth rate).
>
> And so on.
>
> For the second individual starting values are missing from 1996-2000
> First I will have to find the r=growth rate of values from 1991-1995.
> Than the value in 1996 =value in 1995*(1+ growth rate) and
> value in 1997 =value in 1996/(1+ growth rate) and so on.
>
>
> for the last indiviual values are missing from 1995-2000
> if for any indiviual more than 5 values are missing do not fill that.
> any code for this
>
> what i have
>
> what i have
> year name y
> 1990 Aqueela 50.1
> 1991 Aqueela 39.9
> 1992 Aqueela 93.4
> 1993 Aqueela 53.4
> 1994 Aqueela 5.9
> 1995 Aqueela 41.6
> 1996 Aqueela
> 1997 Aqueela
> 1998 Aqueela
> 1999 Aqueela
> 2000 Aqueela
> 1990 Abida 57.0
> 1991 Abida 44.3
> 1992 Abida 41.3
> 1993 Abida 92.3
> 1994 Abida 42.2
> 1995 Abida 56.0
> 1996 Abida
> 1997 Abida
> 1998 Abida
> 1999 Abida
> 2000 Abida
> 1990 Zubaida 68.5
> 1991 Zubaida 51.0
> 1992 Zubaida 41.7
> 1993 Zubaida 91.5
> 1994 Zubaida 40.7
> 1995 Zubaida
> 1996 Zubaida
> 1997 Zubaida
> 1998 Zubaida
> 1999 Zubaida
> 2000 Zubaida
>
> and what i want
>
> year name y
> 1990 Aqueela 50.1
> 1991 Aqueela 39.9
> 1992 Aqueela 93.4
> 1993 Aqueela 53.4
> 1994 Aqueela 5.9
> 1995 Aqueela 41.6
> 1996 Aqueela 96.6
> 1997 Aqueela 113.0
> 1998 Aqueela 132.0
> 1999 Aqueela 154.4
> 2000 Aqueela 180.4
> 1990 Abida 57.0
> 1991 Abida 44.3
> 1992 Abida 41.3
> 1993 Abida 92.3
> 1994 Abida 42.2
> 1995 Abida 82.7
> 1996 Abida 96.6
> 1997 Abida 113.0
> 1998 Abida 132.0
> 1999 Abida 154.4
> 2000 Abida 180.4
> 1990 Zubaida 68.5
> 1991 Zubaida 51.0
> 1992 Zubaida 41.7
> 1993 Zubaida 91.5
> 1994 Zubaida 40.7
> 1995 Zubaida
> 1996 Zubaida
> 1997 Zubaida
> 1998 Zubaida
> 1999 Zubaida
> 2000 Zubaida
>

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