lancedb/docs/web/reranking/index.mdx

---
title: "Reranking Search Results"
sidebarTitle: "Reranking"
description: "Use a reranker to improve search relevance."
icon: "sort-amount-down"
keywords: ["re-ranking", "reranker", "rerank"]
availability:
  oss: available
  enterprise: available
  summary: >-
    Rerankers run in your application after the search returns, so they work
    the same with the embedded library and with a deployment. Most built-in
    rerankers are Python-only.
---

import {
    PyRerankingLinearCombinationUsage,
    PyRerankingRrfUsage,
    PyRerankingCohereUsage,
    PyRerankingMrrUsage,
    PyRerankingCrossEncoderUsage,
} from '/snippets/integrations.mdx';

Reranking is the process of re-ordering search results to improve relevance, often using a
different model than the one used for the initial search. LanceDB has built-in support for reranking
with models from Cohere, Sentence-Transformers, and more.

### Quickstart {#quickstart}

To use a reranker, you run a search and pass the results to the `rerank()` method. The examples below
move from the simplest, model-free rerankers to a model-based one. Each is a complete, runnable script.

**1. Linear combination (simplest).** `LinearCombinationReranker` normalizes the vector and full-text
scores and blends them with a single `weight` (default `0.7`, favoring the vector score). It runs no
model, and reranks [hybrid search](/search/hybrid-search) results.

<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingLinearCombinationUsage}
  </CodeBlock>
</CodeGroup>

**2. Reciprocal Rank Fusion.** `RRFReranker` fuses results by rank position instead of raw score, so it
sidesteps having to make vector and full-text scores comparable. It loads no model either, and it's the
default reranker for hybrid search.

<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingRrfUsage}
  </CodeBlock>
</CodeGroup>

**3. Cohere (model-based).** For higher relevance, a model-based reranker scores each result against the
query with a trained model. `CohereReranker` works with vector, full-text, or hybrid search, and needs
the `cohere` package plus either `COHERE_API_KEY` in the environment or an `api_key` argument.

<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingCohereUsage}
  </CodeBlock>
</CodeGroup>

Reach for the model-free rerankers (`LinearCombinationReranker`, `RRFReranker`) when cost and latency
matter most; reach for a model-based one like `CohereReranker` or `CrossEncoderReranker` when you need
higher relevance and can afford to score every query and document pair with a model.

### Supported Rerankers {#supported-rerankers}

LanceDB supports the following rerankers out of the box. The first three are score-based and run no
model; the rest are model-based. The built-in rerankers are documented in this section; the hosted
providers that need an API key live under [integrations](/integrations/reranking).

| Reranker                    | Default model                          |
| --------------------------- | -------------------------------------- |
| `RRFReranker`               | None (reciprocal rank fusion)          |
| `LinearCombinationReranker` | None (weighted score blend)            |
| `MRRReranker`               | None (weighted reciprocal rank)        |
| `CohereReranker`            | `rerank-english-v3.0`                  |
| `CrossEncoderReranker`      | `cross-encoder/ms-marco-TinyBERT-L-6`  |
| `ColbertReranker`           | `colbert-ir/colbertv2.0`               |
| `AnswerdotaiRerankers`      | `answerdotai/answerai-colbert-small-v1`|
| `JinaReranker`              | `jina-reranker-v2-base-multilingual`   |
| `OpenaiReranker`            | `gpt-4-turbo-preview`                  |
| `VoyageAIReranker`          | No default (model name required)       |
| `WatsonxReranker`           | `cross-encoder/ms-marco-minilm-l-12-v2`|

The model-based rerankers need their provider package installed, and the hosted ones
(`CohereReranker`, `JinaReranker`, `OpenaiReranker`, `VoyageAIReranker`, `WatsonxReranker`) also need an API key, passed
as an `api_key` argument or set in the provider-specific environment variable.

Rerankers add `_relevance_score` and return rows ordered by descending relevance. Python rerankers
accept `return_score="relevance"` or `return_score="all"`; use `"all"` when you want to keep the
original vector distance or FTS score columns for debugging. Model-based rerankers read from
`column="text"` by default, so either return that column in the search results or pass a different
column.

Use `refine_factor` on vector or hybrid queries when you're reranking approximate IVF-PQ results and
want a larger candidate pool before the final ranking step. A value of `3` asks LanceDB to fetch
`limit * 3` candidates, refine them with the full vectors, and keep the requested `limit`. Higher
values can improve recall, but they also increase query latency.

<Note>
**SDK coverage differs across languages**

The provider-specific rerankers in the table above
(`CohereReranker`, `CrossEncoderReranker`, `ColbertReranker`, and others under `lancedb.rerankers`)
are currently **Python-only**. The TypeScript and Rust SDKs currently expose hybrid reranking through
the generic `Reranker` interface (`rerankHybrid` / `rerank_hybrid`) and the built-in `RRFReranker`.
In TypeScript, create the built-in RRF reranker with `await RRFReranker.create(k)`. To use a
model-based reranker from TypeScript or Rust, you must implement the hybrid reranker interface
yourself.
</Note>


### Multi-vector reranking {#multi-vector-reranking}
Most rerankers support reranking based on multiple vectors. To rerank based on multiple vectors, you can pass a list of vectors to the `rerank` method. Here's an example of how to rerank based on multiple vector columns using the `CrossEncoderReranker`:

<CodeGroup>
```python Python icon="python"
from lancedb.rerankers import CrossEncoderReranker

reranker = CrossEncoderReranker()

query = "hello"

# `deduplicate=True` requires `_rowid` on every input result set,
# so call `.with_row_id(True)` on each search before passing it in.
res1 = table.search(query, vector_column_name="vector").limit(3).with_row_id(True)
res2 = table.search(query, vector_column_name="text_vector").limit(3).with_row_id(True)
res3 = table.search(query, vector_column_name="meta_vector").limit(3).with_row_id(True)

reranked = reranker.rerank_multivector([res1, res2, res3], deduplicate=True)
```
</CodeGroup>

- Passing `deduplicate=True` to `rerank_multivector(...)` raises a `ValueError` if any of the
input result sets is missing the `_rowid` column. Therefore, it's recommended to add `.with_row_id(True)` to every
`table.search(...)` call before reranking, or omit `deduplicate=True` if you don't need it.
- `RRFReranker.rerank_multivector(...)` always requires `_rowid` on its inputs, regardless of
the `deduplicate` flag.

## Creating Custom Rerankers {#creating-custom-rerankers}

LanceDB also allows you to create custom rerankers by extending the base `Reranker` class. The custom reranker
should implement the `rerank` method that takes a list of search results and returns a reranked list of
search results. This is covered in more detail in the [creating custom rerankers](/reranking) section.

## Reciprocal rank fusion {#rrf}

## Reciprocal Rank Fusion Reranker

**Reciprocal Rank Fusion (RRF)** is a model-free way to merge several ranked result lists into a
single ordering. Rather than comparing raw similarity scores (which aren't directly comparable
across, say, a vector search and a full-text search), RRF looks only at each document's *rank
position* in each list. It scores every document with the formula `1 / (rank + K)`, sums those
contributions across the lists, and re-sorts by the total. Documents that rank highly in more than
one search rise to the top. Because there's no model to load or call, it's fast and cheap, which is
why it's the default reranker for LanceDB hybrid search. The implementation follows the
[Cormack et al. paper](https://plg.uwaterloo.ca/~gvcormac/cormacksigir09-rrf.pdf).

> **Supported query types:** hybrid search and [multi-vector reranking](/reranking#multi-vector-reranking).
> Because RRF fuses two or more ranked lists, it can't rerank a single vector or full-text result set
> on its own. Calling `rerank_vector` or `rerank_fts` on an `RRFReranker` raises `NotImplementedError`.


<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingRrfUsage}
  </CodeBlock>
</CodeGroup>

### Accepted Arguments {#rrf-accepted-arguments}
| Argument | Type | Default | Description |
| --- | --- | --- | --- |
| `K` | `int` | `60` | A constant used in the RRF formula (default is 60). Experiments indicate that k = 60 was near-optimal, but that the choice is not critical. |
| `return_score` | `str` | `"relevance"` | Options are "relevance" or "all". The type of score to return. If "relevance", will return only the `_relevance_score`. If "all", will return all scores from the vector and FTS search along with the relevance score. |

`K` must be greater than `0`. In TypeScript, construct the built-in reranker with
`await RRFReranker.create(k)` before passing it to `.rerank(...)`.

### Multi-vector reranking {#rrf-multi-vector-reranking}

`RRFReranker` can also fuse the results of several vector searches with `rerank_multivector`, applying
the same rank-fusion algorithm across more than two lists. Every input result set must include the
`_rowid` column, so add `.with_row_id(True)` to each `table.search(...)` call before reranking,
otherwise the call raises a `ValueError`. See [multi-vector reranking](/reranking#multi-vector-reranking)
for a full example.

### Supported Scores for each query type {#rrf-supported-scores-for-each-query-type}
You can specify the type of scores you want the reranker to return. The following are the supported scores for each query type:

#### Hybrid Search {#rrf-hybrid-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Returned rows only have the `_relevance_score` column. |
| `all` | ✅ Supported | Returned rows have vector(`_distance`) and FTS(`score`) along with Hybrid Search score(`_relevance_score`). |

## Linear combination {#linear-combination}

## Linear Combination Reranker

> **Note:** This reranker is deprecated. Use the `RRFReranker` if you need a score-based reranker.

The Linear Combination Reranker combines the results of semantic and full-text search using a linear combination of the scores. The weights for the linear combination can be specified, and defaults to 0.7, i.e, 70% weight for semantic search and 30% weight for full-text search.

> **Note:** Supported query type – Hybrid search only.


<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingLinearCombinationUsage}
  </CodeBlock>
</CodeGroup>

### Accepted Arguments {#linear-combination-accepted-arguments}
| Argument | Type | Default | Description |
| --- | --- | --- | --- |
| `weight` | `float` | `0.7` | The weight to use for the semantic search score. The weight for the full-text search score is `1 - weight`. |
| `fill` | `float` | `1.0` | Score used when a result is missing from one side of the hybrid query. The default strongly penalizes missing vector or FTS matches. |
| `return_score` | `str` | `"relevance"` | Options are "relevance" or "all". The type of score to return. If "relevance", returns only `_relevance_score`. If "all", returns all scores from the vector and FTS search along with the relevance score. |

`weight` must be between `0` and `1`. If either the vector or FTS side returns no rows, the reranker
returns the non-empty side with `_relevance_score` attached rather than failing.


### Supported Scores for each query type {#linear-combination-supported-scores-for-each-query-type}
You can specify the type of scores you want the reranker to return. The following are the supported scores for each query type:

#### Hybrid Search {#linear-combination-hybrid-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Results only have the `_relevance_score` column |
| `all` | ✅ Supported | Results have vector(`_distance`) and FTS(`score`) along with Hybrid Search score(`_distance`) |

## MRR {#mrr}

## MRR Reranker

This reranker uses the Mean Reciprocal Rank (MRR) algorithm to combine and rerank search results from vector and full-text search. You can use this reranker by passing `MRRReranker()` to the `rerank()` method. The MRR algorithm calculates the average of reciprocal ranks across different search results, providing a balanced way to merge results from multiple ranking systems.

> **Note:** Supported query types – Hybrid and Multivector search.

<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingMrrUsage}
  </CodeBlock>
</CodeGroup>

### Accepted Arguments {#mrr-accepted-arguments}
| Argument | Type | Default | Description |
| --- | --- | --- | --- |
| `weight_vector` | `float` | `0.5` | Weight for vector search results (0.0 to 1.0). |
| `weight_fts` | `float` | `0.5` | Weight for FTS search results (0.0 to 1.0). |
| `return_score` | `str` | `"relevance"` | Options are "relevance" or "all". The type of score to return. If "relevance", will return only the `_relevance_score`. If "all", will return all scores from the vector and FTS search along with the relevance score. |

**Note:** `weight_vector` + `weight_fts` must equal 1.0.

For multivector reranking, input result sets need `_rowid` so LanceDB can identify the same row
across the ranked lists. Add `.with_row_id(True)` to each vector search before passing the results
to the reranker.

### Supported Scores for each query type {#mrr-supported-scores-for-each-query-type}
You can specify the type of scores you want the reranker to return. The following are the supported scores for each query type:

#### Hybrid Search {#mrr-hybrid-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Results only have the `_relevance_score` column. |
| `all` | ✅ Supported | Results have vector(`_distance`) and FTS(`score`) along with Hybrid Search score(`_relevance_score`). |

#### Multivector Search {#mrr-multivector-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Results only have the `_relevance_score` column. |
| `all` | ✅ Supported | Results have vector distances from all searches along with `_relevance_score`. |

## Cross encoder {#cross-encoder}

## Cross Encoder Reranker

This reranker uses Cross Encoder models from sentence-transformers to rerank the search results. You can use this reranker by passing `CrossEncoderReranker()` to the `rerank()` method. 
> **Note:** Supported query types – Hybrid, Vector, and FTS.


<CodeGroup>
  <CodeBlock filename="Python" language="Python" icon="python">
    {PyRerankingCrossEncoderUsage}
  </CodeBlock>
</CodeGroup>

### Accepted Arguments {#cross-encoder-accepted-arguments}
| Argument | Type | Default | Description |
| --- | --- | --- | --- |
| `model_name` | `str` | `"cross-encoder/ms-marco-TinyBERT-L-6"` | The name of the reranker model to use.|
| `column` | `str` | `"text"` | The name of the column to use as input to the cross encoder model. |
| `device` | `str` | `None` | The device to use for the cross encoder model. If None, will use "cuda" if available, otherwise "cpu". |
| `trust_remote_code` | `bool` | `True` | Passed to Sentence Transformers model loading. Set this to `False` when you only want to load models that do not require custom repository code. |
| `return_score` | `str` | `"relevance"` | Options are "relevance" or "all". The type of score to return. If "relevance", returns only `_relevance_score`. If "all" is supported, returns relevance score along with the vector and/or FTS scores depending on query type. |

The reranker loads the model locally through `sentence-transformers`, so install the local model
runtime dependencies you need, such as PyTorch and any device-specific acceleration packages.

### Supported Scores for each query type {#cross-encoder-supported-scores-for-each-query-type}
You can specify the type of scores you want the reranker to return. The following are the supported scores for each query type:

#### Hybrid Search {#cross-encoder-hybrid-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Results only have the `_relevance_score` column. |
| `all` | ❌ Not Supported | Results have vector(`_distance`) and FTS(`score`) along with Hybrid Search score(`_relevance_score`). |

#### Vector Search {#cross-encoder-vector-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Results only have the `_relevance_score` column. |
| `all` | ✅ Supported | Results have vector(`_distance`) along with Hybrid Search score(`_relevance_score`). |

#### FTS Search {#cross-encoder-fts-search}
|`return_score`| Status | Description |
| --- | --- | --- |
| `relevance` | ✅ Supported | Results only have the `_relevance_score` column. |
| `all` | ✅ Supported | Results have FTS(`score`) along with Hybrid Search score(`_relevance_score`). |

## Building a custom reranker {#custom}

You can build your own custom reranker in LanceDB by subclassing the base `Reranker` class. At a
minimum, you need to implement `rerank_hybrid()`, which is the logic that combines vector and
full-text search results. Beyond that, you can optionally implement `rerank_vector()` and
`rerank_fts()` if you want your reranker to also handle pure vector or pure full-text searches.

Decide up front which surfaces — hybrid, pure vector, or pure full-text — your reranker should
cover, and only override the ones you need. The base class leaves `rerank_vector()` and
`rerank_fts()` unimplemented, so calling `.rerank(...)` on a single-modality search you haven't
overridden raises `NotImplementedError` rather than silently returning unsorted results. That's a
useful guard, but worth knowing about before you wire up a query path you didn't plan for.

The Python base class exposes hybrid, vector-only, and FTS-only rerank hooks. TypeScript and Rust
currently expose the custom reranker interface for hybrid reranking. In Rust, a custom reranker must
also satisfy the trait bounds `Debug + Send + Sync`.

### Interface {#custom-interface}

The `Reranker` base interface comes with a `merge_results()` method that can be used to combine the
results of semantic and full-text search. This is a vanilla merging algorithm that simply concatenates
the results and removes the duplicates without taking the scores into consideration. It only keeps the
first copy of the row encountered. This works well in cases that don't require the scores of semantic
and full-text search to combine the results. If you want to use the scores or want to support
`return_score="all"`, you'll need to implement your own merging algorithm. The base
`return_score` option accepts only `"relevance"` and `"all"`.

Whichever methods you override, your reranker has one job on the way out: attach a
`_relevance_score` column with the most relevant rows at the top. LanceDB will reject the result
if that column is missing, and downstream `.limit(...)` calls trust the order you return, so
sort descending before handing the table back.

For vector-only reranking in Python, pass a text query to `.rerank(..., query_string="...")`.
The vector query itself may be numeric, but `rerank_vector(query, vector_results)` still receives
a string query so your reranker can score each candidate against the user's text intent.

Below, we show the pseudocode of a custom reranker that combines the results of semantic and full-text
search using a linear combination of the scores:

<CodeGroup>
```python Python icon="python"
from lancedb.rerankers import Reranker
import pyarrow as pa

class MyReranker(Reranker):
    def __init__(self, param1, param2, ..., return_score="relevance"):
        super().__init__(return_score)
        self.param1 = param1
        self.param2 = param2

    def rerank_hybrid(self, query: str, vector_results: pa.Table, fts_results: pa.Table):
        # Use the built-in merging function
        combined_result = self.merge_results(vector_results, fts_results)

        # Do something with the combined results
        # ...

        # Return the combined results
        return combined_result

    def rerank_vector(self, query: str, vector_results: pa.Table):
        # Do something with the vector results
        # ...

        # Return the vector results
        return vector_results

    def rerank_fts(self, query: str, fts_results: pa.Table):
        # Do something with the FTS results
        # ...

        # Return the FTS results
        return fts_results
```
</CodeGroup>

### Example {#custom-example}

As an example, let's build custom reranker that enhances the Cohere Reranker by accepting a filter
query, and accepts any other `CohereReranker` params as `kwargs`.

<CodeGroup>
```python Python icon="python"
from typing import List, Union
import pandas as pd
from lancedb.rerankers import CohereReranker

class ModifiedCohereReranker(CohereReranker):
    def __init__(self, filters: Union[str, List[str]], **kwargs):
        super().__init__(**kwargs)
        filters = filters if isinstance(filters, list) else [filters]
        self.filters = filters

    def rerank_hybrid(self, query: str, vector_results: pa.Table, fts_results: pa.Table)-> pa.Table:
        combined_result = super().rerank_hybrid(query, vector_results, fts_results)
        df = combined_result.to_pandas()
        for filter in self.filters:
            df = df.query("not text.str.contains(@filter)")

        return pa.Table.from_pandas(df)

    def rerank_vector(self, query: str, vector_results: pa.Table)-> pa.Table:
        vector_results = super().rerank_vector(query, vector_results)
        df = vector_results.to_pandas()
        for filter in self.filters:
            df = df.query("not text.str.contains(@filter)")

        return pa.Table.from_pandas(df)

    def rerank_fts(self, query: str, fts_results: pa.Table)-> pa.Table:
        fts_results = super().rerank_fts(query, fts_results)
        df = fts_results.to_pandas()
        for filter in self.filters:
            df = df.query("not text.str.contains(@filter)")

        return pa.Table.from_pandas(df)
```
</CodeGroup>

<Card icon="lightbulb">
Under the hood, `vector_results` and `fts_results` are PyArrow tables. You can learn more about
PyArrow tables [here](https://arrow.apache.org/docs/python). The advantage of PyArrow tables is their
interoperability -- you can easily convert them to Pandas/Polars DataFrames, `PyDict`, `PyList`, etc.

The benefits are also bidirectional -- just as you can easily convert PyArrow tables _to_ Pandas
DataFrames using the `to_pandas()` method -- you can perform DataFrame transformations
and just as easily convert the DataFrame back to PyArrow tables using `pa.Table.from_pandas()` method
as shown in the example above.
</Card>

## Evaluating hybrid search {#eval}

Hybrid search is an often misused and/or misunderstood term. In this section, we're using
the definition of "hybrid search" to mean using a combination of keyword-based and vector search.
Because the vector search operates in a dense embedding space and keyword-based search operate
in a sparse embedding space, their relevance scores cannot be directly compared.
Combining results from multiple searches thus requires a reranking step.

Before evaluating hybrid search, build an FTS index on the text column and use a table with embedding
metadata or explicit query vectors for the vector side. Otherwise the evaluation is measuring setup
fallbacks or errors rather than the reranker.

### Reranking strategies {#eval-reranking-strategies}

There are two common approaches for reranking search results from multiple sources.

- **Score-based**: Calculate final relevance scores from the individual search algorithm scores. Examples: Reciprocal Rank Fusion (the default in LanceDB), mean reciprocal rank fusion, and weighted linear combination of semantic and keyword-based search scores.

- **Relevance-based**: Discards the existing scores and calculates the relevance of each search result-query pair. Example: Cross Encoder models

<Info>
If you call `.rerank()` on a hybrid query without passing a reranker, LanceDB defaults to
`RRFReranker()` — a score-based reranker that uses Reciprocal Rank Fusion. This is the
score-based path most readers encounter first; `LinearCombinationReranker` is an alternative
score-based strategy you opt into explicitly.
</Info>

By default, rerankers return `_relevance_score`. Pass `return_score="all"` when a reranker
supports it, and you also need the original vector or FTS scores for debugging.
Evaluation code can rely on returned rows being ordered by descending `_relevance_score`. Empty
reranked result sets still include the `_relevance_score` column.

The hybrid `rerank(...)` method also accepts a `normalize` argument that controls how the raw
vector and FTS scores are made comparable before reranking:

- `normalize="score"` (the default) — normalizes the raw vector and FTS scores directly.
- `normalize="rank"` — converts each result list to ranks first, then normalizes.

This choice materially affects score-based rerankers (such as `LinearCombinationReranker`), so
when you evaluate score-based strategies, treat `normalize` as a tunable hyperparameter
alongside the reranker itself.

For score-based evaluation, the main built-in knobs are:

- `RRFReranker(K=60)`: rank fusion with a positive smoothing constant.
- `MRRReranker(weight_vector=0.5, weight_fts=0.5)`: weighted reciprocal rank fusion where the weights must sum to `1.0`.
- `LinearCombinationReranker(weight=0.7, fill=1.0)`: blends vector and FTS scores directly; `fill` controls how strongly to penalize a result missing from one side.

Even though there are many more strategies for reranking, there are no "universally best"
ones that work well for all cases, because reranking quality is dataset and application specific.
Evaluating whether a reranking strategy is a good fit is also a challenge. In the next
section, we discuss an example evaluation of different reranking strategies on a sample dataset.

### Example evaluation {#eval-example-evaluation}

The table below shows our evaluation results from an experiment comparing multiple rerankers on
~800 hybrid search queries. This is a modified version of an evaluation script by
[LlamaIndex](https://github.com/run-llama/finetune-embedding/blob/main/evaluate.ipynb) that measures
hit-rate \@ top-k.

#### Using OpenAI `text-embedding-ada-002` {#eval-using-openai-text-embedding-ada-002}

Vector Search baseline: **0.64**

| Reranker | Top-3 | Top-5 | Top-10 |
| --- | --- | --- | --- |
| Linear Combination | `0.73` | `0.74` | `0.85` |
| Cross Encoder | `0.71` | `0.70` | `0.77` |
| Cohere | `0.81` | `0.81` | `0.85` |
| ColBERT | `0.68` | `0.68` | `0.73` |

<img src="https://github.com/AyushExel/assets/assets/15766192/d57b1780-ef27-414c-a5c3-73bee7808a45" />


#### Using OpenAI `text-embedding-3-small` {#eval-using-openai-text-embedding-3-small}

Vector Search baseline: **0.59**

| Reranker | Top-3 | Top-5 | Top-10 |
| --- | --- | --- | --- |
| Linear Combination | `0.68` | `0.70` | `0.84` |
| Cross Encoder | `0.72` | `0.72` | `0.79` |
| Cohere | `0.79` | `0.79` | `0.84` |
| ColBERT | `0.70` | `0.70` | `0.76` |

<img src="https://github.com/AyushExel/assets/assets/15766192/259adfd2-6ec6-4df6-a77d-1456598970dd" />

### Conclusion {#eval-conclusion}

The results show that the reranking methods can significantly improve the search relevance. However,
the improvement we saw was not consistent across all rerankers. In reality, the choice of reranker
likely depends on the dataset and the application.

It's also important to note that the reranking methods are not a
replacement for the search methods they supplement. They are complementary and it's likely that you'd
have to tune them together to get the best results. The latency vs. recall tradeoff is also an
important factor to consider when choosing the reranker. Hopefully this evaluation
gives you a starting point for your own experiments with hybrid search in LanceDB!