On Tue, 1 May 2018, Noel Chiappa via cctalk wrote:
My message to this list was as much a warning, as it was a query if anyone
had any idea why this was happening, or if they'd seen similar behaviour
before.
There are several parts of the eBay search system that are broken.
I have had items show up that absolutely did NOT match my search, and
items fail to show up that definitely DID match.
Adding additional OR'ed terms (eBay does OR with comma delimited list in
parentheses) sometimes results in FEWER hits, when that SHOULD always give
more hits (not all of which are relevant, of course). There is no valid
situation where an additional OR'ed term should reduce recall.
The change of category is reprehensible.
It is an incompetent attempt to increase PRECISION at the expense of
RECALL. (cf. Buckland,Grey
http://www.academia.edu/11944516/The_Relationship_between_Recall_and_Precision
My claim to fame is pointing out that when looking at the limits, that all
four sides of that parallelogram need to be noticed.)
But sometimes RECALL IS your primary concern. (cf. trademark search, or
rare eBay items) You may tolerate some false hits to get ALL of the
hits.
If I'm looking for a red Swingline stapler, I want PRECISION.
If I'm looking for a side-swivel-head stapler for saddle stitching
booklets, I want RECALL.
Quick example: there are a number of other items named "Nextec", other
than Craftsman cordless tools. But a search for "Nextec" in "All categories"
automagically changes to "Power Tools", excluding the others (cellphone
accessories, lasers, technical equipment, line of clothing,...) Even the
[RARE] Craftsman Nextec cordless power pole pruner is usually not listed
in the "Power Tools" section. I am looking for one of those; I do NOT
want it excluded.
