[Discuss] How Daylight Saving Time Messes With Hospitals

[Bill Ricker]

Date/time calculations not using a library accessing the historical
TZ/DST data in Olsen TZdata file is erroneous.
Alas for future dates, one can't even assume the TZ spec won't change
between now and then, as it can be undone by politicians, witness
Morocco cancelling DST with two days' notice recently.

On Tue, Nov 6, 2018 at 6:20 PM Mike Small <smallm at sdf.org> replied:
> If database programmers would only always use UTC for their storage
> format and translate as necessary for presentation it wouldn't be so
> bad,


Right on.
If a Date-Time isn't marked with explicit TZ indicator (including DST
status indication ) it better be implicitly Zulu or it is buggy data
already.

> but I guess in your example case it's too late now.

yeah, should have fixed that in 1999 ...

> Maybe you'd like this article if you haven't seen it already:
> http://naggum.no/lugm-time.html

Interesting


On Tue, Nov 6, 2018 at 7:08 PM Rich Pieri <richard.pieri at gmail.com> re-replied
> If hospitals and doctors from the 2000s and 1990s and 1980s and 1970s
> and 1960s and 1950s and... only always used UTC for their records...
> but they didn't.

If they at least annotate 2018 Nov 4, 1:30 AM EDT vs Nov 4, 1:30 AM
EST, and also 1972 October 29, you're good, you can use TZdata to
validate and convert UTC for storage.

If they failed to note TZ during that hour because the hospital never
moves so they don't need a TZ the rest of the year on paper, well
yeah, it's ambiguous data -- and banning DST in the future won't fix
your ambiguous historical data. And our modern systems can require
recording of the TZ/DST in effect at time of
admission/birth/time-of-other-service at point of data capture going
forward, so you get no value from banning DST.

(Although most people who SAY they want to ban DST, particularly in
N.E.,  actually mean they want to abandon Winter time and move
permanent summer time, UTC-4, which would be DST-less AST.)

> It's not just my example case. An EMR system today has to accomodate
> not only data today but data spanning the entire lifetimes of patients
> with all of the inconsistencies of different paper records and
> procedures and EMRs and timekeeping. And it's impossible to unify
> because the information needed to unify those records does not exist,
> never did.

Yes, you have data ingest problem when pulling in old paper records
and records sent over in incomplete exchange formats from other
systems.
Ambiguous data that wasn't properly cleaned at the time will always be
ambiguous.
Unless you borrow a timemachine and kill Ben Franklin so the idea of
DST never spreads, you can't fix that. (I think he did more good than
harm, so I recommend against it.)

OTOH, TimeZones were created for the convenience of the Railroads and
their passengers, and welcomed by the financial markets, and DST was
promulgated for the convenience of Little League and out-door chores
like lawn mowing (before power mowers it took longer). They were never
welcomed by farmers, who worked can-to-can't and milked the cows at
the same sun-time -- and customers thinking time changed rankled them!

Today, the digital financial markets handle TZ differences between
LON, NYC/BOS, CHI, SF, TOK, and HK markets without difficulty -- and
we trade around the clock. Boston's small stock exchange could go on
Atlantic time without discouraging volume; opening "floor" trading an
hour before New York might actually attract volume.

As more and more parks and ballfields have flood lights, does DST buy
us anything that wouldn't better be addressed by WFH and Flex Time?
No.  Flex time reduces congestion and would encourage bicycling later
in the year.

 If we wanted to join India and Newfoundland as rebels, we could even
split off N.E. as a half-hour timezone based on our local meridian, or
adopt permanent DST by joining NB/NS/PEI as AST (but without ADT/DST).

20 years ago either permanent DST (=AST year round) or half-hour zone
would not have been practical because network TV only recognized 2 TZ,
ET & PT, but with streaming/binging/DVR today, would anyone care if
GoT came on an hour "later" in Boston just as it is an hour "earlier"
in Chicago today?

-- 
Bill Ricker
bill.n1vux at gmail.com
https://www.linkedin.com/in/n1vux