# Field value factor FunctionScore doesn't change score

**URL:** https://discuss.elastic.co/t/field-value-factor-functionscore-doesnt-change-score/371265
**Category:** Elasticsearch
**Tags:** vector-search
**Created:** [November 30, 2024, 4:33pm UTC](https://discuss.elastic.co/t/field-value-factor-functionscore-doesnt-change-score/371265 "2024-11-30T16:33:04Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![sashaepstein2](https://avatars.discourse-cdn.com/v4/letter/s/c2a13f/32.png) [@sashaepstein2](https://discuss.elastic.co/u/sashaepstein2)
#### Post date: [November 30, 2024, 4:33pm UTC](https://discuss.elastic.co/t/field-value-factor-functionscore-doesnt-change-score/371265/1 "2024-11-30T16:33:04Z")

</div>

I added FunctionScore with the FieldValueFactor function to my KNN query, but the search hits scores don't get influenced by the numeric value in the fieldValueFactor.field. I can see the scale of the scores changing when I increase fieldValueFactor.factor or FunctionScore.weight.  
The same happens with other than FieldValueFactor functions.  
Either, I am doing this wrong, or ES doesn't support FunctionScore with the KNN query. My ES server is v8.15.4  
Here is the relevant excerpt from the ES query I am sending:  
"query":{  
"bool":{  
"must":{  
"function\_score":{  
"query":{  
"knn":{  
"field":"vector",  
"query\_vector":[....],  
"filter":[  
. . . .  
]  
}  
},  
"functions":[{  
"field\_value\_factor":{  
"field":"TwitterScore",  
"factor":1.2,  
"missing":1  
}]  
. . . . . . .