If you're searching for the word "pitcher", your results may relate to either baseball players or containers for liquids. For a search in the context of baseball, you might want to completely exclude results that contain the words "glass" or "water" by using the `must_not` clause. However, if you want to keep those results but downgrade them in relevance, you can do so with `boosting` queries.
A `boosting` query returns documents that match a `positive` query. Among those documents, the ones that also match the `negative` query are scored lower in relevance (their relevance score is multiplied by the negative boosting factor).
## Example
Consider an index with two documents that you index as follows:
```json
PUT testindex/_doc/1
{
"article_name": "The greatest pitcher in baseball history"
}
```
```json
PUT testindex/_doc/2
{
"article_name": "The making of a glass pitcher"
}
```
Use the following match query to search for documents containing the word "pitcher":
```json
GET testindex/_search
{
"query": {
"match": {
"article_name": "pitcher"
}
}
}
```
Both returned documents have the same relevance score:
```json
{
"took": 5,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 0.18232156,
"hits": [
{
"_index": "testindex",
"_id": "1",
"_score": 0.18232156,
"_source": {
"article_name": "The greatest pitcher in baseball history"
}
},
{
"_index": "testindex",
"_id": "2",
"_score": 0.18232156,
"_source": {
"article_name": "The making of a glass pitcher"
}
}
]
}
}
```
Now use the following `boosting` query to search for documents containing the word "pitcher" but downgrade the documents that contain the words "glass", "crystal", or "water":
```json
GET testindex/_search
{
"query": {
"boosting": {
"positive": {
"match": {
"article_name": "pitcher"
}
},
"negative": {
"match": {
"article_name": "glass crystal water"
}
},
"negative_boost": 0.1
}
}
}
```
{% include copy-curl.html %}
Both documents are still returned, but the document with the word "glass" has a relevance score that is 10 times lower than in the previous case:
```json
{
"took": 13,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 0.18232156,
"hits": [
{
"_index": "testindex",
"_id": "1",
"_score": 0.18232156,
"_source": {
"article_name": "The greatest pitcher in baseball history"
}
},
{
"_index": "testindex",
"_id": "2",
"_score": 0.018232157,
"_source": {
"article_name": "The making of a glass pitcher"
}
}
]
}
}
```
## Parameters
The following table lists all top-level parameters supported by `boosting` queries.
Parameter | Description
:--- | :---
`positive` | The query that a document must match to be returned in the results. Required.
`negative` | If a document in the results matches this query, its relevance score is reduced by multiplying its original relevance score (produced by the `positive` query) by the `negative_boost` parameter. Required.
`negative_boost` | A floating-point factor between 0 and 1.0 that the original relevance score is multiplied by in order to reduce the relevance of documents that match the `negative` query. Required.
