Module
Module 4 of 6Lesson 1 of 2~16 min

QA and monitor data collection

One wrong number on a dashboard can steer an entire roadmap before anyone notices. This lesson shows a PM how to check an event before release, monitor collection afterward, and investigate an anomaly before reading it as a change in behavior. These habits prevent decisions made on top of a bug.

Take this lesson: your first course is freeSee the full syllabus

Lesson objective

By the end of this lesson, you will be able to QA an event before release, set up simple collection monitoring (volumes, ratios, reconciliation with the database) and diagnose a data anomaly before drawing a product conclusion from it.

Topics covered

  • data quality
  • tracking QA
  • volume monitoring
  • schema validation

Where it fits

Reliable, compliant data

How do I know my numbers are right, and that I collect them by the rules?

Lessons in this module

  1. QA and monitor data collection (this lesson)
  2. Collect by the rules, consent, CNIL and minimisation

What you will learn in the course

This lesson is part of the course Instrument a product and use data to make decisions

  • Build a product's metrics tree (North Star, input metrics, guardrails) from the decisions to be made, and rule out vanity metrics.
  • Design an implementable tracking plan (events, properties, naming convention, identity and accounts, emitting source, owners).
  • QA and monitor event collection to get reliable data, and know what to do when it is not.
  • Collect usage data in line with the GDPR and the CNIL rules (consent, audience measurement exemption, minimisation, retention period).
  • Analyse a conversion funnel, activation and cohort retention, and interpret the resulting curves correctly.
  • Choose a product analytics tool (PostHog, Amplitude, Mixpanel, GA4, data warehouse) based on needs, constraints and cost.
  • Turn an analysis into a reasoned decision (dashboard, decision memo) while avoiding interpretation traps (vanity, Simpson, correlation, small counts).

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