Guides / Algolia AI

Dynamic Re-Ranking

The relevance of your search results often changes with time, and it can change fast. Take a generic drug-store as an example. Customers that searched for “mask” before February 2020 (the outbreak of the COVID-19 pandemic) most probably were looking to buy facial masks to take care of their skin. During the pandemic, however, it’s more likely the users are looking for surgical masks.

To address users’ changing expectations, you might have to continually tweak your results using tools like Rules or optionalFilters. This can become time-consuming quickly because trends come and go fast. A better, more scalable approach is to use Dynamic Re-Ranking.

What is Dynamic Re-Ranking?

Dynamic Re-Ranking is a feature of the Algolia engine that leverages AI to determine trends in your users’ behavior. Based on the query and the position of the result they click or convert, we can make improvements to your relevance by boosting results that are rising in popularity. We can also demote outlier results that sometimes show up because of textual relevance edge cases, but are not actually relevant to your users in the context of a particular query.

Getting back to the generic drug-store example, the Dynamic Re-Ranking feature detects that people searching for “mask” are mostly looking for surgical masks instead of face masks and automatically boosts surgical masks higher in the results. This, in turn, leads to a more relevant search and can result in a higher conversion rate, without you having to create Rules or optionalFilters to tweak your relevance.

This feature is currently in open beta and is available to Standard and Premium plans. After the beta, only Premium plans can access this feature.

Effect on relevance

While Dynamic Re-Ranking can be a powerful tool in tweaking your relevance, we don’t want it to interfere with the relevance you’ve already set up. For this reason, Dynamic Re-Ranking kicks in after our engine has computed the textual relevance of your results and has applied your custom ranking. If you use Rules, we apply them after the Re-Ranking, so that they keep working as expected.

Re-Ranking does not take effect if you enable Personalization and we have enough data to personalize the search. If there’s not enough data to personalize a search, for first-time users, for example, Re-Ranking kicks back in.

We currently don’t apply Re-Ranking on empty searches.

Set up Dynamic Re-Ranking

There are a few prerequisites to set up before you can leverage Dynamic Re-Ranking to improve your relevance automatically.

Click and conversion events

To make use of Dynamic Re-Ranking, you need to send us click and conversion events. Our AI uses this data to detect trends in your users’ behavior and re-rank results based on these trends.

Simulate Re-Ranking

You can simulate Re-Ranking for any of your indices from the AI Re-Ranking page in the dashboard. On this screen, you can try out any query you want, and see how Dynamic Re-Ranking affects the results, without activating Re-Ranking on your live index.

Simulating Dynamic Re-Ranking on your indices with the Re-Ranking Simulator

Enable Re-Ranking for production

Before you enable Dynamic Re-Ranking for an index, you should always A/B test your Re-Ranking first.

You can enable Re-Ranking on the AI Re-Ranking page in the dashboard. Select the index you want to activate Re-Ranking for, and press the Activate Re-Ranking button.

A/B test Dynamic Re-Ranking

You should always use A/B tests to test Re-Ranking on an index. This way, you can accurately measure the impact Re-Ranking has on your search. You can create an A/B test for Re-Ranking directly from the AI Re-Ranking page in the dashboard, by clicking the Launch an A/B test button at the top right of the page. Clicking this button shows a form that allows you to quickly create an A/B test with the desired traffic split and duration. You can also set filters so that we only re-rank records that match this specific filter. This way, you can prevent, for example, items that are not in stock from being promoted by Dynamic Re-Ranking.

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