# Significant Terms Recommendations

**URL:** <https://discuss.elastic.co/t/significant-terms-recommendations/137964>\
**Category:** Elasticsearch\
**Created:** [June 29, 2018, 12:39pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964 "2018-06-29T12:39:37Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![bruno\_z](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bruno_z/32/61143_2.png) [@bruno\_z](https://discuss.elastic.co/u/bruno_z)\
**Post date:** [June 29, 2018, 12:39pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/1 "2018-06-29T12:39:37Z")

</div>

I'm new to elasticsearch and Im developing product recommendation like 'People who bought this, also bought...'

I have an index named "products" which I use for faceted filtering (prices, category, brand and so on...), each document in that index has all the informations needed to show a full page of products. So with just one query in elasticsearch, I can build the page.  
For the recommendation system, I thought about using the significant terms in my completed orders, so I can suggest products bought together to a X product that was added in cart.  
​  
So the index would be something like this:

```
/orders
{"products": ["sku1", "sku2", "sku3", "sku4"]}
{"products": ["sku1", "sku2", "sku3"]}
{"products": ["sku1", "sku3", "sku3", "sku5"]}
...

```

when I query, using significant terms from elastic search, the result will be something like this:

```
[
{key: "sku1", score: 0.8},
{key: "sku2", score: 0.5},
...
]

```

With that I have the identifiers (sku's) from products, but I dont have all the information, is it right doing two queries to build my recommendation shelf?  
And what if I wanted to recommend products filtering by price? (eg. products bought together but with price lower than $80) I would need to query in products by sku and price?

---

<div class="post-metadata">

**Author:** ![Mark\_Harwood](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mark_harwood/32/10538_2.png) [@Mark\_Harwood](https://discuss.elastic.co/u/Mark_Harwood)\
**Post date:** [June 29, 2018, 12:58pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/2 "2018-06-29T12:58:40Z")

</div>

If I understand your example correctly you're using previous orders to make the associations between products. So the index you will be querying is the `orders` index and looking for significant terms in the `products` field.  
You say that you also want to then filter the product suggestions by price - you are right that this would need to be handled in your app using a subsequent query on an different index like `products` where given the sku you can get the price (and colour/size etc).  
You should be able to set the `size` parameter on the significant\_terms agg to something large e.g. 10000 skus to give you a large base to then filter. Looking up many IDs in a search may prove to be expensive.

You could try filter the significant\_terms agg with a query for orders with products not exceeding the required price range but that might be over-aggressive as whole orders may be filtered if they contain expensive products that are nothing to do with your search term or suggested "also-boughts.

---

<div class="post-metadata">

**Author:** ![bruno\_z](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bruno_z/32/61143_2.png) [@bruno\_z](https://discuss.elastic.co/u/bruno_z)\
**Post date:** [June 29, 2018, 1:10pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/3 "2018-06-29T13:10:34Z")

</div>

Hi Mark, thanks for your reply  
Yes, you are right, I'm using previous order to do the recommendation system.

Any idea of a recommendable size that would not be expensive if I decide to query products index by skus?

How would be the `orders` index to query for products within a price range? Since this information is only available in `products` index

---

<div class="post-metadata">

**Author:** ![Mark\_Harwood](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mark_harwood/32/10538_2.png) [@Mark\_Harwood](https://discuss.elastic.co/u/Mark_Harwood)\
**Post date:** [June 29, 2018, 1:16pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/4 "2018-06-29T13:16:17Z")

</div>

> [@bruno\_z](#):
>
> How would be the `orders` index to query for products within a price range?

I presumed orders might contain prices. Ignore me if not.

> [@bruno\_z](#):
>
> Any idea of a recommendable size that would not be expensive

"It depends" - on your data ad hardware. Benchmarking is the way forward.

---

<div class="post-metadata">

**Author:** ![bruno\_z](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bruno_z/32/61143_2.png) [@bruno\_z](https://discuss.elastic.co/u/bruno_z)\
**Post date:** [June 29, 2018, 1:24pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/5 "2018-06-29T13:24:28Z")

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Yes, it contains prices, but the problem is that the products price changes frequently, so it wouldn't be easy to keep it synchronized. And maybe I would like to filter by other properties (category, brand, ...)

Ok, lets say I dont want to filter the products returned by the significant terms. I would need the same way to do a subsequent query to get the products information within `products` index, querying just by the skus. This is a right approach?

---

<div class="post-metadata">

**Author:** ![Mark\_Harwood](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mark_harwood/32/10538_2.png) [@Mark\_Harwood](https://discuss.elastic.co/u/Mark_Harwood)\
**Post date:** [June 29, 2018, 1:46pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/6 "2018-06-29T13:46:38Z")

</div>

You'd want to query the `products` index - use a `bool` query with 2 `must` or `filter` clauses - one is a `terms` query listing the skus and the other is a `range` query with the price restriction

---

<div class="post-metadata">

**Author:** ![bruno\_z](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bruno_z/32/61143_2.png) [@bruno\_z](https://discuss.elastic.co/u/bruno_z)\
**Post date:** [June 29, 2018, 4:13pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/7 "2018-06-29T16:13:48Z")

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Thanks Mark

I'll try it

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 27, 2018, 4:13pm UTC](https://discuss.elastic.co/t/significant-terms-recommendations/137964/8 "2018-07-27T16:13:52Z")

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