Hi John,

We can look at query sessions with some level of effort, but the tools I
was using do not. This was just a quick stab at a question the came up when
Mikhail and I were talking: could Relevance Forge be used to see what kind
of difference a simple rule makes for poorly performing queries? (Yes, yes
it can!)

We don't, that I know of, track user sessions like that at query time. It's
technically possible, I'm sure, but we don't want to, say, store query info
in local storage of the browser, and it might be too expensive to compare
earlier queries in the sequence in real time anyway.

I would definitely not suggest just turning off ? over the weekend or
anything like that. I'd want to reach out to the community and also
investigate more queries that use ? to try to figure out what they are
doing. But it's clear from the queries I've looked at—considering how many
start with who, what, when, where, how, will, do, etc.—that a lot of people
are just asking questions, and those queries can do poorly as a result.

We've recently brainstormed about an expert mode, where, among other
things, ambiguous search syntax (like ?) could be interpreted as actual
search syntax, while the default casual user mode treats question marks as
just question marks. It's not going to happen anytime real soon, but it's
good to think about.

—Trey



On Fri, May 27, 2016 at 5:32 PM, John R. Frank <[email protected]> wrote:

> Hi Trey,
>
> Cool analysis. I'm curious whether the infrastructure let's you look at
> query sessions---- do these queries with special symbols occur late in a
> multi-query sequence that included simpler versions earlier in the
> sequence?
>
> Maybe you can segment users who are confused about the query language
> versus power users who are iteratively enhancing a query. The latter seems
> likely to generate low-result-count queries that are more acceptable
> because the user up twisted the query intentionally.
>
>
> John
>
>
> Sent from +1-617-899-2066
>
> On May 27, 2016, at 5:17 PM, Trey Jones <[email protected]> wrote:
>
> Hi everyone,
>
> Mikhail, Data Analyst Extraordinaire, recently published his report, "From
> Zero to Hero"[1] on the relationship between various features of queries as
> strings (rather than the content of the query) and those queries getting no
> results.
>
> Today for my 10% project I took a quick look at the two most impactful
> features, quotes and question marks. These two features stood out in
> Mikhail's report as having both relatively high volume and a relatively
> higher chance of getting no results.
>
> I'm not planning on doing a more formal report right now, though I will
> probably copy this email to my Notes page.
>
> Quotes make sense, as we try to get an exact match for strings inside
> quotes, which limits our options for making a match. Question marks are
> actually a little-known, little-used, poorly documented, and poorly
> understood wildcard: they stand for any single character. Most users use
> them to ask questions.
>
> I took a random sample of 50,000 English Wikipedia queries (using my
> now-favorite criteria at [2]—basically, full text queries from normal
> humans (as best as we can tell) with fewer than 3 results). I extracted all
> the queries with quotes (170) and all the queries that ended in question
> marks, that is, looked like questions (274). There were 4 queries that were
> all questions and spaces (e.g., ???? ???????? ????)—they caused problems as
> they are very expensive queries that repeatedly failed on the test cluster,
> so I discarded them. I also took a random sub-sample of 1K queries from the
> larger sample of 50K.
>
> All samples had plenty of gibberish queries (e.g.,
> "fhdsfhsdjkfgdsjklgsdl"?), queries in other languages, and the other usual
> cruft.
>
> *For the sample with quotes,* I used Relevance Forge to compare the
> results of running queries as is vs replacing quotes with spaces. The
> summary stats are below. The zero results rate for queries with quotes went
> down by almost half, and more than half of queries has changes in their top
> 5 results. The TotalHits stats are wildly skewed by one query that
> increased it's results by over 300,000. (There always seems to be an
> outlier!)
>
> *Metrics:*
>    *Query Count:* 170
>       Num TotalHits Changed: μ: 3049.99; σ: 26435.14; median: 1.00
>
>    *Zero Results:* 38.2% (-37.1%)
>    *Top 5 Sorted Results Differ:* 51.8%
>    *Top 5 Unsorted Results Differ:* 51.2%
>       Num Top 5 Results Changed: μ: 2.14; σ: 2.30; median: 1.00
>
> *For the sample with question marks, *I used Relevance Forge to compare
> the results of running queries as is vs dropping all trailing question
> marks and spaces. Some queries ended in multiple question marks (removed),
> and some queries had other question marks in the middle of the query
> (kept).  The summary stats are below. The summary is similar to those with
> quotes: almost half of the zero results queries got results, and more than
> half of all queries had changes to their top 5 results, and the mean number
> of total hits is blown out by one query that got more than 300K additional
> results.
>
> *Metrics:*
>    *Query Count:* 274
>       Num TotalHits Changed: μ: 1875.48; σ: 19885.60; median: 1.00
>
>    *Zero Results:* 43.1% (-39.1%)
>    *Top 5 Sorted Results Differ:* 53.3%
>    *Top 5 Unsorted Results Differ:* 53.3%
>       Num Top 5 Results Changed: μ: 2.22; σ: 2.33; median: 1.00
>
> *For the 1K sample query,* I used Relevance Forge to compare the results
> of running queries as is vs (a) replacing quotes with spaces, (b) dropping
> all trailing question marks and spaces, and (c) doing both (there are even
> a very few queries with both quotes and trailing question marks!).
>
> Keep in mind that these are all poorly performing queries (fewer than 3
> results). Summary results:
>
> (a) quotes
> *Metrics:*
>    *Query Count:* 1000
>       Num TotalHits Changed: μ: 0.31; σ: 9.70; median: 0.00
>    *Zero Results:* 79.5% (-0.1%)
>    *Top 5 Sorted Results Differ:* 0.1%
>    *Top 5 Unsorted Results Differ:* 0.1%
>       Num Top 5 Results Changed: μ: 0.01; σ: 0.16; median: 0.00
>
> (b) question marks
> *Metrics:*
>    *Query Count:* 1000
>       Num TotalHits Changed: μ: 0.16; σ: 3.45; median: 0.00
>    *Zero Results:* 79.4% (-0.2%)
>    *Top 5 Sorted Results Differ:* 0.4%
>    *Top 5 Unsorted Results Differ:* 0.4%
>       Num Top 5 Results Changed: μ: 0.02; σ: 0.32; median: 0.00
>
> (c) quotes and question marks (pretty much the sum of the previous two!)
> *Metrics:*
>    *Query Count:* 1000
>       Num TotalHits Changed: μ: 0.47; σ: 10.30; median: 0.00
>    *Zero Results:* 79.3% (-0.3%)
>    *Top 5 Sorted Results Differ:* 0.5%
>    *Top 5 Unsorted Results Differ:* 0.5%
>       Num Top 5 Results Changed: μ: 0.03; σ: 0.35; median: 0.00
>
> Overall, it's a pretty small effect, and a lot of the results are not
> always great when quotes are dropped, but it's a very small effort to make
> the change.
>
> A quick look at the queries with question marks didn't show any that were
> obviously intended to be used as wildcards (except maybe
> all-question-marks, like ????—but who knows what that is supposed to be?).
>
> It has been suggested before and I would also now recommend disabling ? as
> a wildcard—it causes many more problems than it solves.
>
> Re-running poor-performing queries that have quotes without the quotes is
> an easy win. We should do that too!
>
>
> Thoughts, comments, and suggestions welcome!
>
> —Trey
>
> [1]
> https://github.com/wikimedia-research/Discovery-Search-Adhoc-QueryFeatures/blob/master/report.pdf
> [2]
> https://www.mediawiki.org/wiki/User:TJones_(WMF)/Notes/TextCat_Optimization_for_frwiki_eswiki_itwiki_and_dewiki#Random_sampling
>
>
> Trey Jones
> Software Engineer, Discovery
> Wikimedia Foundation
>
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