Re: st: RE: A modest proposal - missing data doesn't count

["Allan Reese (Cefas)" <allan.reese@cefas.co.uk>]

Thanks for all comments.  I'll continue to add -& x<.- to expressions as
-& !mi(x)- requires more typing and -inrange(x,10,.)- excludes the
missing but implements >= not >.

The fuss (addressing Martin's criticism) is that Stata has always been
consistent and logical# on this matter, but Stata users are not
consistent and logical - they're human.  Hence this issue is a pitfall
and I would love to find a way to make it less error prone.  Martin may
get it right every time; other users will not.  Many users of a certain
spreadsheet - or generally, managers of staff who use it - have assured
me, "If people enter the right values, then there is no problem."  If
people always did the right thing, we would not have trains passing red
lights, swabs left inside patients after operations, oil pipe valves
that fail to failsafe ...

It's so easy to forget that x<10 will not be affected by missing values
but x>10 will be.  It would be good to have software that guards against
pitfalls rather than invites you in.

Allan

# Computer logical, but when x is missing x>10 is formally undecided and
the result should be missing.


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