Inspiration

A day in the life of an Experiment Lead

Your first question will probably be: “what the hell is an experiment lead?”. That was my first question as well. My name is Niels, and I work as an experiment lead at Cosmos Collective.

What is it like to be an experiment lead at cosmos collective?

As 75% of the working population on the planet, I start my day with a double espresso, a small bite and a quick shower. The rest of my day is all but repetitive. When arriving at the office, I’ll get my second coffee, and I check all the running advertisements (Google, Facebook, Instagram, Pinterest, Waze and even Tinder!) for our different clients. It’s important to check this daily because you don’t want to spend thousands of euros on ads that don’t do the job. The rest of my day is all but repetitive. 

At Cosmos Collective, we have two types of clients with two different goals who need experimentation. We make business validation and growth marketing tracks. In business validation, we set up hundreds of experiments (no kidding) to (in)validate your idea. We use marketing to track whether your business idea is feasible, viable and desirable. Your idea is as good as the research you did before.

In growth marketing, we grow our clients using marketing based on the data we acquire. 

That’s why I use tools like SEMrush, keywordtool.io, Instapage, Mailchimp and many more every day, all day long, so it’s tough to get bored. But my job is to be fast and precise, and tools help me to accomplish that. Daily I check Product Hunt. This page helps me find new tools that can make my life (and my clients) easier. Want to know which tool I signed up for yesterday? I discovered Framer, a landing page kit that helps me design landing pages quickly and very stylish and professionally.

As an Experiment Lead, guess what? I come up with the experiments. I execute those ideas alongside the experiment designer and follow up together with the client. I am in charge of the project, but I’ll always get the support of the team. From feedback to brainstorm sessions, every time I need something, the team is there to support me and help me overcome challenges.


If you look at my diary, every day it’s like working for a different company. One day I run experiments for one client and the next day for the other. Besides designing and executing the experiments, I’m in close contact with the client, so if you’re considering joining us or become an experiment lead, get ready for an overload of Slack messages, grow your network and especially grow your skillset which is the most important one.


Lunchtime is the hardest part of the day. It’s hard to know what or where we are going to eat. But we all love food. So our lunches vary from picnics in the park to funky lunches at the office. Last Friday was Colombian food, have you ever tried it? (including Margaritas).

Margaritas and Colombian ceviche at Cosmos Collective



Every day is different, and days go by so fast lately, it’s hardly impossible not to like this job with so much variety and challenges. With a lot of work comes a lot of fun as well. We have a great team with lovely colleagues, and we’ll keep growing. 



Inspired & ready for your next job as an experiment lead?

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