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recsyschallenge / 2017

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Clicks for item/user combinations that have no impressions #56

Open hackebeil opened 7 years ago

hackebeil commented 7 years ago

Hi guys.

When looking at the daily interactions, we noticed that there are some clicks by users for certain items where no impression has been recorded previously. Meaning, the interaction data suggests that some items are clicked by users before an impression has been made. The ratio of item/user combinations for which this is the case is not negligible (about 30% in our case). At this moment, this makes it very problematic to analyze the data with performance indicators, since the calculation of, for example, the conversion rate depends on the accuracy of the impression count.

Is this an error or can this be explained by some user behavior?

Cheers

dkohlsdorf commented 7 years ago

Hey, this can be explained since users can click on items in the job search. The item appears in a users search result and the user clicks it. Appearing in the results does not trigger an impression.

Daniel

hackebeil commented 7 years ago

Hi Daniel.

A follow up question: The above mentioned "problem" (click but no impression) also happens for item/user combinations that we actually recommended. Meaning, we recommend item A to user B, user B clicks on item A, but there is no impression for A/B.

Is this due to the filtering you mentioned? And if so, why would you filter item/user combination that would have been successful? Is it just a random subsampling?

Cheers

dkohlsdorf commented 7 years ago

No we filter if a user already received a push recommendation in an 8 hour window. That is our recommender in this case.

Daniel