[news.groups] Cost-per-reader bug found

reid@decwrl.dec.com (Brian Reid) (01/07/88)

A couple of months ago Brad Templeton convinced me to adjust the "cost per
reader" figures to include propagation. This seemed reasonable: if a
newsgroup only has 50% propagation, then it has a cost per kilobyte that is
only half of what a 100% group would have.

Alas, since I'm a dumdum, I multiplied by the propagation percentage, e.g.
50, and not by the propagation fraction, e.g. 0.50. OK, I admit I should have
tested the change, but it seemed so simple.

As a result, the numbers for December are a factor of 100 too large. 
I'm not going to post a revision: even USENET readers can divide by 100.

Brian

jerry@oliveb.olivetti.com (Jerry Aguirre) (01/07/88)

I would suggest that the most serious error in the cost/reader
computation is the one that has the least comment on its accuracy,  the
$.10/minute value.  I don't know how this figure was arrived at but I
can think of at least two reasons why it is too high.

The first is that usenet sites tend to be grouped into clusters.
Looking at the New Jersey and the California bay maps show hundreds of
sites that can call each other with a local call.  I don't pay anything
for my two main feeds, they are local calls.  Two of my "leafs", Tymix
and 3comvax are in the stats and I don't think they pay that kind of rate
either.  (And, of course, phone company sites may or may not pay for
calls and that may or may not represent "real" money.)

The second reason is that some of the connections are over dedicated
links.  Of the 5 sites that I post info on 4 of them are connected over
ethernet and don't pay any phone charges.  In some cases even some of
the long-distance connections are over dedicated (fixed cost) links.  (I
notice that the decwrl-decvax link has a pathalias cost of "LOCAL".)

I know that there are a few sites that are paying a lot more I just
don't think that they will average out with the number that are paying
zero.  So the estimated cost is higher than most pay, not an average,
and lower than some sites pay.  It just isn't any more meaningful than
the bytes/reader data.

Collecting actual costs on a month to month basis is impractical
but couldn't the arbitron configuration include a field to specify
whether the feed(s) were of a particular type, say dedicated,
local-call, zone, long-distance, long-distance-night, pc-persuit, or
arpa?  With that kind of data the cost estimate might be a little more
believable.

					Jerry Aguirre
					Systems Administration
					Olivetti ATC

nyssa@terminus.UUCP (The Prime Minister) (01/07/88)

In article <228@bacchus.DEC.COM> reid@decwrl.UUCP (Brian Reid) writes:
>I'm not going to post a revision: even USENET readers can divide by 100.

Is that 100 binary, octal, decimal, hex or other? :-)

page@ulowell.cs.ulowell.edu (Bob Page) (01/08/88)

A significant percentage of the sites that ship news around over great
distances (the 'backbone'-- however you define that) use NNTP over the
Internet.  That would further reduce the 10c/min transmission cost
figure that Arbitron uses.

..Bob
-- 
Bob Page, U of Lowell CS Dept.  page@ulowell.edu  ulowell!page
"I've never liked reality all that much, but I haven't found a
better solution."		--Dave Haynie, Commodore-Amiga

reid@decwrl.dec.com (Brian Reid) (01/09/88)

I used 10 cents/minute for arbitron because that's the same number that Rick
Adams used (and uses) for his "Traffic for the last 2 weeks " postings, and I
wanted people to be able to compare the numbers for accuracy. (The programs
were independently written and work on slices of USENET taken across the
country from one another, and any discrepancy was interesting to me).

The true cost of carrying a newsgroup is more than just the transfer
charges; there is disk space, CPU time used to run the news software, time
spent expiring it, and so on. Maybe 10 cents per minute is the wrong metric,
and maybe using dollars is the wrong metric, but the *relative* values of the
numbers are quite accurate and it is appropriate to have some non-zero cost
per kilobyte of news. I think I'll start labeling them not in dollars
but in Zlotys or Yuan (two currencies without officlal exchange rates into
dollars).

Brian

geoff@desint.UUCP (Geoff Kuenning) (01/09/88)

In article <12330@oliveb.olivetti.com> jerry@oliveb.UUCP (Jerry Aguirre) writes:

> I would suggest that the most serious error in the cost/reader
> computation is the one that has the least comment on its accuracy,  the
> $.10/minute value.

I agree with Jerry that this is an inaccurate value, but my solution
is to look at the cost/reader as being the middle of a
three-orders-of-magnitude estimate.  In other words, a newsgroup listed
as $2.00/reader actually costs somewhere between $0.20 and $20.00.
Yes it's crude, but then so are the statistics (as Brian is well aware).
-- 
	Geoff Kuenning   geoff@ITcorp.com   {uunet,trwrb}!desint!geoff

michael@stb.UUCP (Michael) (01/16/88)

(Tried to mail this, but it bounced)

Rather than Zlotys or Yuans, how about real currency like Zorkmids
or Federation Credits or ...
-- 
: Michael Gersten		ihnp4!hermix!ucla-an!remsit!stb!michael
:				sdcrdcf!trwrb!scgvaxd!stb!michael
: "A hacker lives forever, but not so his free time"