Sorry I didn't respond to this sooner!

I really like the idea of trying to detect what languages the user can
read, and searching in (a subset of) those. This wouldn't benefit from
relevance lab testing, though. It'll need to be measured against the user
satisfaction metric. (BTW, Do we have a sense of how many users have info
we can detect for this?)

I think the biggest problem with language detection is the quality of the
language detector. The Elastic Search plugin we tested has a Romanian
fetish when run on our queries (Erik got about 38% Romanian on 100K enwiki
searches, which is crazy, and I got 0% accuracy for Romanian on my much
smaller tagged corpus of failed (zero results) queries to enwiki). Most of
the time, I would expect queries sent to the wrong wiki to fail (though
there are some exceptions)—but a query in English that does get hits in
rowiki is going to just look wrong most of the time.

There are several proposals for improving language detection in the
etherpad, and we can work on them in parallel, since any given one could be
better than any other one. (We don't want to make 100 of them, but a few to
test and compare would be nice—there may also be reasonable speed/accuracy
tradeoffs to be made, e.g., 2% decrease in accuracy for 2x speed is a good
deal.)

We need training and evaluation data. I see a few ways of getting it. The
easy, lower-quality way is just take queries from a given wiki and assume
they are in the language in question (i.e., eswiki queries are in Spanish).
Easy, not 100% accurate, unlimited supply. The hard, higher-quality way is
to hand annotate a corpus of queries. This is slow, but doable. I can do on
the order of 1000 queries in a day—more if I were less accurate and more
willing to toss stuff into the junk pile. I couldn't do it for a week
straight, though, without going crazy. A possible middle of the road
approach would be to create a feedback loop and run detectors on our
training data and review and remove items that are not in the desired
language (we could also start by filtering things that are not in the right
character set, like removing all Arabic, Cyrillic, and Chinese from enwiki,
frwiki, and eswiki queries). If we want thousands of hand-annotated
queries, we need to get annotating!

I think we can use the relevance lab to help evaluate a language detector
(at least with respect to zero results rate). We could run the detector
against a pile of zero-results queries, then group the queries by detected
language, and run them against the relevant wiki (if we have room in labs
for the indexes, and we update the relevance lab tools to support choosing
a target wiki to search). We wouldn't be comparing "before" and "after",
but just measuring the zero results rate against the target wiki. As any
time we're using zero-results rate, there's no guarantee that we'll be
giving good results, just results (e.g., "unix time stamp" queries with
English words fail on enwiki but sometimes work on zhwiki for some reason,
but that's not really better.)

I'm somewhat worried about being able to reduce the targeted zero results
rate by 10%. In my test[1], only 12% of non-DOI zero-results queries were
"in a language", and only about a third got results when searched in the
"correct" (human-determined) wiki. I didn't filter bots other than the DOI
bot, and some non-language queries (e.g., names) might get results in
another wiki, but there may not be enough wiggle room. There's a lot of
junk in other languages, too, but maybe filtering bots will help more than
I dare presume.


[1]
https://www.mediawiki.org/wiki/User:TJones_(WMF)/Notes/Cross_Language_Wiki_Searching#Perfect_identification.2C_ignoring_non-language_queries

Trey Jones
Software Engineer, Discovery
Wikimedia Foundation

On Mon, Nov 2, 2015 at 9:03 PM, Erik Bernhardson <[email protected]
> wrote:

> It measures the zero results rate for 1 in 10 search requests via
> CirrusSearchUserTesting log that we used last quarter.
>
> On Mon, Nov 2, 2015 at 6:01 PM, Oliver Keyes <[email protected]> wrote:
>
>> Define this "does it do anything?" test?
>>
>> On 2 November 2015 at 19:58, Erik Bernhardson
>> <[email protected]> wrote:
>> > Now that we have the feature deployed (behind a feature flag), and have
>> an
>> > initial "does it do anything?" test going out today, along with an
>> upcoming
>> > integration with our satisfaction metrics, we need to come up with how
>> will
>> > will try to further move the needle forward.
>> >
>> > For reference these are our Q2 goals:
>> >
>> > Run A/B test for a feature that:
>> >
>> > Uses a library to detect the language of a user's search query.
>> > Adjusts results to match that language.
>> >
>> > Determine from A/B test results whether this feature is fit to push to
>> > production, with the aim to:
>> >
>> > Improve search user satisfaction by 10% (from 15% to 16.5%).
>> > Reduce zero results rate for non-automata search queries by 10%.
>> >
>> > We brainstormed a number of possibilities here:
>> >
>> > https://etherpad.wikimedia.org/p/LanguageSupportBrainstorming
>> >
>> >
>> > We now need to decide which of these ideas we should prioritize. We
>> might
>> > want to take into consideration which of these can be pre-tested with
>> our
>> > relevancy lab work, such that we can prefer to work on things we think
>> will
>> > move the needle the most. I'm really not sure which of these to push
>> forward
>> > on, so let us know which you think can have the most impact, or where
>> the
>> > expected impact could be measured with relevancy lab with minimal work.
>> >
>> >
>> >
>> > _______________________________________________
>> > discovery mailing list
>> > [email protected]
>> > https://lists.wikimedia.org/mailman/listinfo/discovery
>> >
>>
>>
>>
>> --
>> Oliver Keyes
>> Count Logula
>> Wikimedia Foundation
>>
>> _______________________________________________
>> discovery mailing list
>> [email protected]
>> https://lists.wikimedia.org/mailman/listinfo/discovery
>>
>
>
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