[PVRCNC] SS prefills file accuracy in SSB 2008

[Jim Jordan, K4QPL]

Thanks for your work, Kaz.

I also noted quite a few changes to the info in the pre fills in cw as well. 
My ssb accuracy rate is questionable so that one didn't get as much 
attention as cw.  Changes in section are usually because the op moves. The 
checks are harder to determine. I did a couple random checks with last years 
database and found several where the pre-fill agreed with the log submission 
but was different from what they were sending this year. And I say that 
advisedly because whenever a prefill did not agree with my own copy, unless 
I was 100% sure I would ask for a confirmation, particularly where the op 
was sending his exchange manually. It's easy to get on autopilot and send 
what someone else sends you, or what you see in the log or whatever. Some 
actually changed back to the prefill check when queried! At least that kept 
ME from being charged with the error.
Several ones that had unexplained changes became obvious when looking at the 
database. It was K4XXX @ N3YYY so the op probably used his own check. And 
yes, some of them were just flat wrong. Even so, having something there 
improves rate and accuracy because you are comparing with something. As you 
say, log what you hear, but I'm very curious to see my LCR since this is the 
first time I've used prefills and I'm hopeful my accuracy will improve.

73,

Jim, K4QPL
----- Original Message ----- 
From: "KAZeringue" <kazeringue at aol.com>
To: "PVRCNC" <pvrcnc at mailman.qth.net>; <pvrc at mailman.qth.net>
Sent: Saturday, November 22, 2008 1:40 PM
Subject: [PVRCNC] SS prefills file accuracy in SSB 2008


> Just in case anyone gives a rat's fuzzy hind-quarters....
>
> Here are a few observations and notes about the prefill file some of you 
> may have used for SS SSB.
>
> After the contest, I solicited logs from AA4NC, N1LN, and KA1ARB.  My 
> intention is to use their logs to build a more robust sample set for the 
> 2009 season.  They have all agreed and sent me their data.  (Thanks!)
>
> I was also curious after the SSB Sweeps to see how accurate the prefills 
> data may have been, so I thought I'd pass along what I have found.
>
> Background:
> The most comprehensive of the prefills files for 2008 SSB was built from 3 
> sources.  Actual log data from N4AF, ARRL CW SS log data from the ARRL 
> scores database, and ARRL SSB SS log data from the ARRL scores database.
>
> The three data sources were applied to one another in the order outlined 
> above, and in chronological order.
>
> The intention for 2009 is to include the additional log data from AA4NC, 
> N1LN, and KA1ARB.  This should add value by including data for casual 
> contesters who may not ever actually submit logs to ARRL.
>
> Observations:
> After the contest AA4NC brought up a few questions about discrepancies he 
> had found.  I expected there would be some, so once I got the logs from 
> the gang I was able to slice and dice a bit.
>
> I looked at only the discrepancies/errors for the "check" and the 
> "section".  I'm sure the discrepancy in the precedence field is much 
> higher - but folks change class a lot, so I don't care.
>
> Check number errors:
> Across all three sample logs, the error rate in the prefills seems to be 
> about four percent.
>
> I have found one source of error that seems easily explained.  The ARRL 
> database data for some of these errors contained a '00' check number for 
> some callsigns' MOST RECENT entry.  A look at the
> scores data for prior years shows a uniform check value in prior years.
>
> This seems to be a case of someone submitting a log without having filled 
> in their own exchange info. (Note: As a writelog user, I know that this is 
> possible with writelog.  All too easy a mistake to make!)
>
> That accounted for just under a third of the errors.
>
> In comparing the discrepancies in AA4NC vs KA1ARB vs N1LN, I found that 
> the contestants had indeed logged the same check numbers.  I expect that 
> means the prefills file was incorrect, as the three top NC ops are 
> unlikely to all make the same logging error.  This covers almost all of 
> the other errors.  Some of that is probably folks using different checks, 
> guest ops, etc.  But some is just plain errors in the prefills. No known 
> explanation for these errors(yet).
>
> The final group are uniques in each of the three logs.  I figure the 
> prefills are wrong rather than the contestants, but it could be either.
>
> Summary on check numbers:
> Expect to see about a four percent error rate in the prefills data for the 
> check number.
>
> Section Errors:
> The discrepancies in the section ran just under half of the discrepancies 
> in the check number.  If comes out to be about 1.5 percent.  No research 
> on the possible reasons for those yet.
>
> Conclusions:
> Looking at only three sample logs showed very similar discrepancy rates 
> with the prefills, so I expect the following advice to be valid.
>
> 1) Log what you hear!
>
> 2) Expect four percent error on the check, about two percent error on the 
> section.
>
> 3) I expected higher discrepancy rates than these, so at this point I 
> don't see much reason to change my basic methodology.  For 2009, I'll 
> produce the data in much the same way, sequences adjusted for the mode of 
> the current contest.
>
> I don't know what sort of accuracy anyone expected with these exchange 
> files, but now you have a baseline on the error rates in the one produced 
> for 2008.
>
> 73 es cu in ARRL 160m de w4kaz
>
>
>
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