You're viewing version 2.8 of the OpenSearch documentation. This version is no longer maintained. For the latest version, see the current documentation. For information about OpenSearch version maintenance, see Release Schedule and Maintenance Policy.
Ranking evaluation
The rank eval endpoint allows you to evaluate the quality of ranked search results.
Path and HTTP methods
GET <index_name>/_rank_eval
POST <index_name>/_rank_eval
Query parameters
Query parameters are optional.
| Parameter | Data type | Description |
|---|---|---|
| ignore_unavailable | Boolean | Defaults to false. When set to false the response body will return an error if an index is closed or missing. |
| allow_no_indices | Boolean | Defaults to true. When set to false the response body will return an error if a wildcard expression points to indexes that are closed or missing. |
| expand_wildcards | String | Expand wildcard expressions for indexes that are open, closed, hidden, none, or all. |
| search_type | String | Set search type to either query_then_fetch or dfs_query_then_fetch. |
Request fields
The request body must contain at least one parameter.
| Field Type | Description |
|---|---|
| id | Document or template ID. |
| requests | Set multiple search requests within the request field section. |
| ratings | Document relevance score. |
| k | The number of documents returned per query. Default is set to 10. |
| relevant_rating_threshold | The threshold at which documents are considered relevant. Default is set to 1. |
| normalize | Discounted cumulative gain will be calculated when set to true. |
| maximum_relevance | Sets the maximum relevance score when using the expected reciprocal rank metric. |
| ignore_unlabeled | Defaults to false. Unlabeled documents are ignored when set to true. |
| template_id | Template ID. |
| params | Parameters used in the template. |
Example request
GET shakespeare/_rank_eval
{
"requests": [
{
"id": "books_query",
"request": {
"query": { "match": { "text": "thou" } }
},
"ratings": [
{ "_index": "shakespeare", "_id": "80", "rating": 0 },
{ "_index": "shakespeare", "_id": "115", "rating": 1 },
{ "_index": "shakespeare", "_id": "117", "rating": 2 }
]
},
{
"id": "words_query",
"request": {
"query": { "match": { "text": "art" } }
},
"ratings": [
{ "_index": "shakespeare", "_id": "115", "rating": 2 }
]
}
]
}
Example response
{
"rank_eval": {
"metric_score": 0.7,
"details": {
"query_1": {
"metric_score": 0.9,
"unrated_docs": [
{
"_index": "shakespeare",
"_id": "1234567"
}, ...
],
"hits": [
{
"hit": {
"_index": "shakespeare",
"_type": "page",
"_id": "1234567",
"_score": 5.123456789
},
"rating": 1
}, ...
],
"metric_details": {
"precision": {
"relevant_docs_retrieved": 3,
"docs_retrieved": 6
}
}
},
"query_2": { [... ] }
},
"failures": { [... ] }
}
}