This, and related questions, have often been
discussed on Statalist and I continue to get
private emails about such questions
for reasons that will become clear.
Here is my version of the facts.
A key principle here is that authors
are to be considered responsible for and
knowledgeable about their programs, rather than
Statalist collectively.
0. -kernreg- was published by the original
authors in STB-30.
1. -kernreg1- was published by Xavi Ramos
via Statalist as a partial fix of
various bugs in the original.
2. -kernreg2- was published by me as
a fuller fix, ditto. It does not
have a separate help file, as it just
does what -kernreg- claims to do,
or so I believe.
As I recall, there were emails on
Statalist of the form "-kernreg- doesn't
work", which is why people watching the
list posted 1 and then 2. The original
authors are not, or have not remained,
members of Statalist.
The normal etiquette, and here I put
on a hat as an Editor of the Stata Journal,
which superseded the STB in 2001,
would be for the original authors to re-release
-kernreg- with bug fixes, so that -kernreg2-
at least can then be zapped as irrelevant. (If
this happened, we would try to contact Xavi Ramos,
the author of -kernreg1-, and ask him to remove it
from SSC. I don't know without checking if he
is on the list.)
But despite several public and private requests
to do this the original authors have never got round
to it.
However, and to cut this long story short,
I consider -kernreg- to be part
of history. -locpoly- is a much better and
more up-to-date program.
(So, why then does (e.g.) -kernreg2- remain visible?
Because, whether or not I like it, people still
insist on downloading -kernreg- and using it.
If they are on Stata <= 7, -locpoly- is no use
to them. At least -kernreg2- remains visible to those
who look carefully.)
In short, this is a small mess, but you can
cut straight through and use -locpoly- instead.
Incidentally, a simple
. search kernel regression
would have pointed directly at -locpoly-.
I'd add a not-so-subtle pointer to the
different but not completely different -mrunning-
which can handle multiple predictors.
Nick
[email protected]
A Briggs
> I want to run a kernel regression of y on x with the ultimate
> aim to plot
> the smoothed y on x. Searching for user-written programs I have found
> kernreg, kernreg1 and kernreg2 which are exactly the commands I want.
>
> However, it appears that these commands are fairly old and graph the
> smoothed y on x using pre-stata 8 graph styles. I can easily
> get around
> this by storing the smoothed variable and the grid-points and
> then plotting
> those variables in stata 8 but I was wondering if this
> program has been
> updated recently so I can run what I want in one line and not have to
> generate new variables?
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