reid@decwrl.dec.com (Brian Reid) (04/03/88)
A lot of people have noticed that news.announce.conferences turns up at the top of the arbitron readership list month after month, and are skeptical that it is really that popular. Here's what is going on. The definition of "X reads Y" used by arbitron is that user X has in his .newsrc file at least one unexpired message marked as read. The assumption is that the expire program is run at regular intervals and that if the reader has stopped reading the group, that sooner or later the last message read by this person will expire and then he will no longer be taken to be a reader. Every message posted to news.announce.conferences has an expiration date that is very far in the future. Specifically, the announcement for a conference does not expire until the conference happens. Because some conference organizers send out very early announcements, it is fairly common for messages to sit around in that newsgroup for as long as a year. As a result, if a person looks at news.announce.conferences once a year, he is counted as an active reader, because he has an unexpired message marked as read. There's really no way around this. Arbitron is dependent on the record-keeping schemes used by the news programs, and none of the various news programs that exists (B news, C news, "3.0 news", etc.) has any explicit support in them for readership measurement. I have to deduce readership from information that they leave lying around. In this case the information is somewhat misleading, but it's the best that can be done. On June 20, the IVP/ODE conference announcement that was posted in May 1987 will expire. This will immediately fix part of the problem, but as long as these announcements regularly sit around for a year or more, the measurement will always be a little bit peculiar. Note that the measurements are not completely wrong, because in order to be counted a user must have looked at that group at least once, which in some perverse sense counts as reading the group. Brian Reid
roy@phri.UUCP (Roy Smith) (04/04/88)
reid@decwrl.UUCP (Brian Reid) writes: > if a person looks at news.announce.conferences once a year, he is counted > as an active reader, because he has an unexpired message marked as read. > > There's really no way around this. Sure there is. For each article marked as read, see if the modification time on the file in /usr/spool/news is within the default expiration time for that system. The cost to do this may turn out to be prohibitive, but it's certainly possible. -- Roy Smith, {allegra,cmcl2,philabs}!phri!roy System Administrator, Public Health Research Institute 455 First Avenue, New York, NY 10016
reid@decwrl.dec.com (Brian Reid) (04/04/88)
>> if a person looks at news.announce.conferences once a year, he is counted >> as an active reader, because he has an unexpired message marked as read. >> >> There's really no way around this. > Sure there is. For each article marked as read, see if the >modification time on the file in /usr/spool/news is within the default >expiration time for that system. The cost to do this may turn out to be >prohibitive, but it's certainly possible. Let me rephrase my statement, then. There is really no practical way around this.