[tz] How good is pre-1970 time zone history represented in TZ database?

[Clive D.W. Feather]

Alois Treindl said:
>    I have analyzed to what extent TZ database represents the time zone
>    information correctly, for these data.
> 
>    I think the results are of some interest for the TZ community.
> 
>    The overall sums are:
> 
>    tz_count    24'674'767  data records, 100%
>    tz_irange   23'675'636 in time range and region which TZ covers
>    correctly, 96%
>    tz_good        736'769 in time range and region where TZ is unreliable,
>    but correct, 3%
>    tz_bad         262'362 in time range and region where TZ database gives
>    false result. 1%

Can you please explain how you've done this analysis. In particular, how do
you know that TZ is "unreliable, but correct" or gives a bad result?

-- 
Clive D.W. Feather          | If you lie to the compiler,
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