Define retention
Separate cohort membership from qualifying return activity.
Business and customer analytics · EDITION 1.0.0
Measure Retention with Cohort Analysis
Build calendar-month activity cohorts from event records, distinguish mature zeroes from unavailable cells and write a bounded retention readout.
By Sanjaay Gowda T S · For product analysts, customer success teams and practical data learners.
You need: Basic spreadsheet arithmetic and familiarity with the topic; Python 3.10+ and a terminal for the optional companion project
Runtime and hardware details
Python 3.10 or later and a terminal. The supplied project runs locally and uses the Python standard library.
No model, API key, cloud account or network calls are used by the companion.
Basic spreadsheet arithmetic and familiarity with the topic; Python 3.10+ and a terminal for the optional companion project.
Full setup and scope ↓$2.99USD · one-time purchase
Prepared with AI assistance. Independent human technical, editorial and assistive-technology reader review remains pending. Automated checks and agent review are not certification.
PDF + EPUB + companion project. Any applicable tax is shown at checkout. Single-reader ebook terms; companion code is MIT licensed.
TRY THE FREE SAMPLE
See how the guide teaches.
Read 6 sample pages to explore the introduction, first chapter and teaching approach before you choose the complete edition.
Read free sample PDF · No checkout required
WHAT YOU WILL LEARN
Understand each part.
Inspect every boundary.
Handle maturity
Preserve unknown future cells instead of filling them with zero.
Explain comparisons
Report counts and definition changes beside retention rates.
INSIDE THE BOOK
9 focused chapters.
- Define membership and return
- Choose a time axis and maturity rule
- Prepare users and events
- Calculate a fixed-denominator table
- Read differences without assuming causes
- Segment without losing the denominator
- Run the cohort calculator
- Audit tracking and identity changes
- Turn retention findings into a learning plan
Your download includes
- 21-page tagged PDF with linked contents
- Reflowable EPUB for ebook readers
- Local Python project, fictional input, recorded expected JSON output and 10 companion tests
- 3 explanatory diagrams
- 9 chapters with exercises and worked answers
Before you begin
Python 3.10 or later and a terminal. The supplied project runs locally and uses the Python standard library.
No model, API key, cloud account or network calls are used by the companion.
Learning prerequisites: Basic spreadsheet arithmetic and familiarity with the topic; Python 3.10+ and a terminal for the optional companion project.
Prepared with AI assistance. Independent human technical, editorial and assistive-technology reader review is pending.
The included examples are synthetic teaching material. Model access, software subscriptions, hosting, ongoing updates and consulting are not included.
CLEAR EXPECTATIONS
Before you buy.
What will I build?
Build calendar-month activity cohorts from event records, distinguish mature zeroes from unavailable cells and write a bounded retention readout. The local companion uses fictional teaching fixtures. Project limits: Input dates must already be converted to the agreed reporting timezone. The tool uses calendar-month activity, not survival analysis or rolling retention. Fixed user identifiers may not equal people or accounts.
What was tested?
The 10 companion tests passed on the packaged project. The supplied fictional fixture produced its recorded expected JSON output. EPUBCheck reported no errors or warnings; DAISY Ace and PDF/UA automated checks passed. These local teaching checks are not production accuracy claims or certification. Independent human technical, editorial and assistive-technology reader review remains pending.
How do I get the files?
Complete the secure Lemon Squeezy checkout to access the PDF, EPUB and companion ZIP. Keep your receipt and download access private. This is a one-time purchase of edition 1.0.0; ongoing updates and consulting are not included.
Can I share the book or the companion code?
The full ebook is licensed to one reader. The labelled free sample may be shared unchanged. The companion project is MIT licensed and may be adapted or shared with its licence notice. See the exact ebook terms.
Keep membership fixed, distinguish incomplete periods, and explain what return means
One book. A complete learning project. Evidence you can inspect.
AI-assisted · Independent human review pending
$2.99USDBuy ebook