Multiple word searches have missing results

[sidharthramesh]

Search for "Abdominal Pain":

http://localhost:8080/v1/snomed/search?s=abdominal - Returns a lot of results
http://localhost:8080/v1/snomed/search?s=abdominal+p - No results
http://localhost:8080/v1/snomed/search?s=abdominal+pa - No results
http://localhost:8080/v1/snomed/search?s=abdominal+pai - Returns a lot of results

Hermes always returns 0 results / 404 error when the second word has less than 3 characters.

[wardle]

This is working as designed.... but the question is... is it the right design....

So there are some autocompletion things that use the whole phrase - as you are doing... but there are others for speedy data entry like 'comm acq pne' that I want to be able to type and autocomplete. So I limit search to minimise too much thrashing to autocomplete a token for three or more. So for your example, expert users are more likely to type abd pai and get what they want - in my clinic I'm never going to type out the word abdominal!

So the question is... am I wrong? Should we be autocompleting on phrase or token, and at what threshold?

One option would be to remove the restriction if there is more than one token. That would mean 'abd p' will work, but I should like to run some tests to see how Lucene manages with a single char prefix. Another option would be to use a different approach for phrase completion, but then you have to type the whole of the first word... which I promise you don't want to force users to do!

The relevant code is here. Each token is combined logically, rather than using Lucene MultiPhraseQuery or similar. I believe MultiPhraseQuery would autocomplete 'abdominal p' but not 'abd pai'. Could add an option to permit a single char prefix search iff the total character count is above two...

[wardle]

Also remember that in real usage, you'd always have a constraint on there. Entering a problem list or list of diagnosis for example you'd limit and it's very likely your user would have started typing and selected abdominal pain before typing any more than abdom.

[sidharthramesh]

I am limiting the searches to Events and Clinical Findings. And most of the people using my autocomplete will not have any sort of training, so I need to make it as intuitive as possible.

Typing 'adb' does bring up abdominal pain, however, it's the fourth option.

The natural tendency is for them to type 'abd p' or 'abdominal p' (for users with no understanding of the autocomplete) until 'Abdominal pain' is the first result.

However, when no results are returned they are signalled into thinking that there are no matches for 'abd p' so they infer there won't be any matches for 'abd pai' either, and stop typing! They never get to 'abd pai'.

One fix I could do would be to check if the words other than the first word are less than 3 characters in length and encourage them to keep typing. But I think it's bad UX. Better feedback would be for them to see the results they saw earlier filtering out as they type.

Even when someone is searching for "Community acquired pneumonia" they search for 'com ac' or 'com acq p' before reaching the full 'com acq pne' . When there are no results in the middle, it gives them a scare and they think no terms will match their search.

And this only happens when there are two words. The search still works when they search for single characters.

So there is no way that the user will be able to deduce that more than 3 characters are needed for the non-second word without training and instruction.

Removing the 3 character limit from Lucene would be a good start. You can see if it messes up the other searches, and if it doesn't that would be a welcome addition.

[wardle]

There are UI examples in which search only begins once you've typed a minimum number of characters. But google now manages with only a single letter. I've done some testing and it looks fine to remove the check on the prefix search - ie allow prefix search for any length of term. It will need careful use of max-hits - and of course the ECL implementation uses this - but let me know how you get on.

Fixed in 2cfabd5 see new release 0.6.2.

[sidharthramesh]

Thank you! I will test it today and let you know.

[sidharthramesh]

Works as expected 🎉🎉
A much improved search experience in my opinion!

[wardle]

Glad it worked. It seemed better in my testing as well so thank you for suggesting.