A pupil’s week long internship in our Recsys team.

By: CriteoLabs / 04 Oct 2017

In France, pupils ending their middle school studies have to perform a one week observation internship in a company. The goal of this internship is to help students have a firsthand experience with work-life in a company and help them decide on their future career paths. This seems logical as they do not have enough skills to tackle “real-world” development tasks.
Or do they?

When Nicolas Jonasz , (a middle school student) who had already done his mandatory internship in an architecture company, reached out to me to know whether he could come intern for one week at Criteo, I replied “Sure, but are you ready to do some real work?”. He quickly affirmed his decision to join us for a week.

One month before his arrival, I sent Nicolas a couple of tutorials about Python and some simple exercises on data analysis and plotting, because he was just starting to learn about programming. When he arrived at Criteo, he was ready. In 2 days, instead of  a week, he coded a visualization tool able to aggregate multiple features and help us analyse faster the results of our A/B tests.

During the next three days, he went far above our expectations by coding an algorithm to detect outliers, the local outlier factor1. As a benchmark, we compared it to scikit-learn’s outlier detection example and the performance is comparable with other proposed algorithms. Obviously, the code can still be optimized but it provides a strong basis for, eg, discovering faulty partners in our online tests for example.


In a nutshell, although Nicolas was a middle school intern in our team for a week, he added value helped us in spotting regressions in our AB test analysis. This further shows our team’s push in always getting the best of its engineers by providing them with the best supervision and challenges to help in achieving amazing results. If you love problem solving and curious about an adventure in Criteo R&D, click here for more.

Post written by

Alexandre Abraham

Software Engineer, R&D


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