Welcome to Data Analysis Journal

Go behind the scenes of genuine data analysis and data storytelling.

Data Analysis Journal is a weekly newsletter and advice column about data analysis, data science, and product analytics. Trusted by thousands of analysts and data scientists around the world, it aims to bridge the gap between academic knowledge and industry requirements.

I’m Olga, an analyst and data scientist. Born in Ukraine and based in San Francisco. I am a head of a product analytics team at MyFitnessPal and previously worked at Change.org, Microsoft, First Republic Bank, and quite a few big and small startups that paid me in knowledge and cookies. 

My superpower is that I specifically pay significant attention to user engagement and behavior analytics by identifying product personas, developing quantitative and qualitative user profile analyses, building feature usage matrices, and proving relationships between user engagement and revenue. I have never seen revenue growth with low product usage and poor engagement. That’s why I closely watch the DAU/MAU ratio, user retention, and CFO state of mind.

In my free time, I usually stare coldly into foreboding time series charts until they permanently burn into my eyes. When I am not doing that, I write about all the data things people make me do at work with the hope to expand and advance analytics.

With over a decade of trial and error, I share what good or bad analysis practice is, what framework to use to best solve a challenge, what interviewers look for, how to hire the best talent, and how to successfully structure and grow data teams.

You can find me on Twitter and LinkedIn.

When you subscribe to Data Analysis Journal, you will receive:

  • SQL and Python solutions, interview questions, and guidance.

  • Deep dives and analytical case studies.

  • Data analysis project examples and walkthroughs.

  • Examples of successful (and not really) A/B tests, rollout procedures, and their analysis.

  • Insights from data analytics and data science experts.

  • My frameworks and playbooks for analysis, reporting, metric calculations, test evaluations, and forecasts. 

What readers say

“Olga's data analysis journal helped me switch careers from consulting to Tech because I was able to develop a Product analytics mindset through her articles on user retention, cohort analysis, product adoption, and SQL Interview questions.“ - Sangamitra, Product Analyst

“In addition to being full of resources, Olga's newsletter provides a crucial framework for understanding the practice of data analysis. Read it to gain insight into real-world analytics problems and find ways to improve your own skills.” - Lira, Analytics Manager

“Olga's newsletter is a one-stop-shop for all of your data-related resources, whether you're starting out new in the industry or a seasoned data enthusiast - you'll find great information that'll help expand your data world! I love the wide variety of topics this newsletter covers that you'll be sure to learn something new from it. I'm so glad to have this newsletter as a resource when I transitioned into the industry last year. I call this my e-mentor! “ - Helen, Data Scientist

“I’m a Product Manager, and I always struggled with analytics. This journal provides the right guidance for me like - what to look for running tests, conversions to track, rates and metrics to know. Must read for every Product Manager.” - Jonathan, Product Manager

“I’ve been reading Olga’s newsletter for as long as I can remember. As someone new to the industry her newsletter felt like having a personal data mentor showing me the do’s, don’ts, and what’s new in the industry. It’s a must-read for anyone starting out in the industry or wanting to keep up in the industry i.e everyone!” - Adaobi, Analyst

“I find the Journal is quite helpful for staying in the loop of things. With how fast-moving technology is, it can be quite difficult to keep track of everything that’s happening out there. Having a newsletter compile all the interesting tidbits helps immensely. Also good for browsing through other’s projects for inspiration, or reading interesting data stories!” - Aaisha, Data Scientist

Random post picks

Data analysis

Read more - Data Analysis Journal - Product Analysis



Read more - A/B Testing


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Read more - Data Analysis Journal - SQL

Posting schedule

  • Paid subscribers will receive one newsletter a week and get full access to the website along with my mentorship and support.

  • Free subscribers will receive one newsletter per month.

Proceeds from subscriptions are donated to Ukrainian Children's Aid and Relief Effort charity.

If your company would like to purchase a group subscription at a discounted rate, click here:

Get a group subscription

If you are looking for a job, and can’t afford a paying subscription at the moment, please email me at olga@berezovsky.me, and I will set you up!

I love what I do, and my mission is to show you just how exciting and impactful data analysis can be.

Subscribe to Data Analysis Journal

Where product, data science, and analytics intersect. Trusted by thousands of analysts and data scientists around the world


Olga Berezovsky 
Medieval Analyst who loves data  and analysis and writes about fun things people make her do at work