# How to do MoreLikeTHESE in Elastic Search?

**URL:** <https://discuss.elastic.co/t/how-to-do-morelikethese-in-elastic-search/17992>\
**Category:** Elasticsearch\
**Created:** [June 9, 2014, 12:14pm UTC](https://discuss.elastic.co/t/how-to-do-morelikethese-in-elastic-search/17992 "2014-06-09T12:14:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Alain\_Desilets](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/alain_desilets/32/29314_2.png) [@Alain\_Desilets](https://discuss.elastic.co/u/Alain_Desilets)\
**Post date:** [June 9, 2014, 12:14pm UTC](https://discuss.elastic.co/t/how-to-do-morelikethese-in-elastic-search/17992/1 "2014-06-09T12:14:06Z")

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I just LOVE the MoreLikThis (MLT) feature of ElasticSearch and am finding  
new and interesting ways of using it all the time.

However these days, I find myself needing a MoreLikeTHESE feature. In other  
words, given a group of documents that fit together, I want to find other  
documents that might belong in that group.

Is there a "native" way of doing that with the ES API? For example, is it  
possible to do MoreLikeThis on an Aggregation? I looked in the API  
documentation and didn't find anything.

If this is not supported natively, what would be the "best" way to  
implement this using the existing blocks? I can think of at least two:

== Approach 1: Concatenated Pseudo-Document ==

Create a pseudo-document whose content is the concatenation of the content  
of all documents in the group. Add that "document" to the index, then do  
the regular MoreLikeThis on that document.

The disadvantage of this approach is that the Pseudo-Document could become  
very large.

== Approach 2: Multiterm Vector Pseudo-Document ==

Retrieve the multiterms of all the documents in the group. Create a pseudo  
document that contains only the most frequent or most "important"  
multi-terms.

Do the regular MoreLikeThis on this pseudo-document.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 1:23am UTC](https://discuss.elastic.co/t/how-to-do-morelikethese-in-elastic-search/17992/2 "2017-07-06T01:23:48Z")

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