Email Campaign Metrics: What Opens and Clicks Can Tell You
Why email open rates are unreliable, where bot clicks come from, and how to tie an email campaign to website results with UTM parameters and GA4 key events.
Read articleIndependent web analytics specialist
Notes from the work.
Clear explanations of analytics, privacy, implementation, and the evidence behind better decisions.
Latest writing.
Indexing and Crawling: What an Analyst Needs to Check
A page missing from Google is a crawl, index, canonical or discovery problem. Check robots.txt, noindex, canonicals and sitemaps in a fixed diagnostic order.
Read articleStructured Data and Social Metadata: Different Jobs, Different Checks
Schema.org
Read articleRegular Expressions for Analytics: Matching and Testing URLs
Learn to write and test regex for analytics URLs with positive and negative cases, and see how GTM, GA4 and Data Studio differ on partial and full matching.
Read articlePower BI Data Models and Measures: A Practical Starting Point
Build a Power BI star schema: set the fact table grain, create one-to-many relationships, and write an average order value DAX measure you can check by hand.
Read articlePandas for Analysts: Cleaning and Checking a Small Dataset
A worked pandas example: clean a hypothetical orders export, remove duplicates, group revenue by channel and check row counts and totals against the input.
Read articleA Small Python Workflow for an Analytics Task
Turn one repeated spreadsheet task into a small Python script: a virtual environment, one package, readable functions, a debugger session and a clear failure.
Read articleGTM Environments: When Separate Environments Help
Decide whether Google Tag Manager environments fit your setup. Base it on staging servers and the release process, not on languages, markets or habit.
Read articleWhy Old Values Persist in the GTM Data Layer: Merge, Clear and Callbacks
A worked example of why stale values survive in the GTM data model, how null, undefined and ecommerce: null clear them, and how eventCallback timing works.
Read articleBuilding and Testing a GTM Custom Template, From Code to Gallery
Build a GTM custom tag template in one workflow: sandboxed JavaScript, narrow permissions, unit tests with mocks and the files the template gallery needs.
Read articleGoogle Ads Conversion Tracking: Measurement and Verification
Set up one Google Ads purchase conversion with value, currency, transaction ID and enhanced conversions, then verify it in Tag Assistant and diagnostics.
Read articleMeta Conversions API: Event Flow, Deduplication and Validation
How a Meta Conversions API server event pairs with the browser Pixel event, how event_id deduplication works, how to hash customer data, and how to validate it.
Read articleImplementing Meta Pixel and Checking Consent Behaviour
Set up Meta Pixel in GTM with one of two consent patterns, then check in DevTools and Meta tools what it loads, sends and stores before and after consent.
Read articleServer-Side GTM Hosting: Comparing Options and Running Costs
Compare server-side GTM hosting on Cloud Run and managed providers on equal terms, then estimate monthly cost for a hypothetical site with checked arithmetic.
Read articleDesigning a Server-Side Measurement Architecture
Map the data flow of a server-side GTM setup: browser, consent, tagging server, clients, tags, vendors, custom domain and logging, with a decision checklist.
Read articleServer-Side Tagging: When It Is Worth the Extra System
Server-side GTM adds data control, but also a server to run. Learn what it improves, what it does not change, and five conditions for deciding to use it.
Read articleWardley Mapping for Analytics: What to Build, Buy or Standardise
Map one analytics decision by user need and evolution to see which parts to build, which to buy and which to standardise, and where the map stops helping.
Read articleCritical Chain for Analytics Projects: Dependencies, Constraints and Buffers
Plan an analytics tracking project with Critical Chain: find the resource constraint, size a buffer and track it, shown on a worked hypothetical example.
Read articleDelegating Analytics Work: A Clear Brief, Ownership and Review
How to delegate analytics work: write a brief with outcome and acceptance criteria, set who decides what, agree review points and define when to ask for help.
Read articleCynefin: Choosing an Approach to an Unfamiliar Analytics Problem
Cynefin helps analysts match the method to the situation. A hypothetical revenue drop split into clear, complicated, complex and chaotic parts shows how.
Read articleDocker for Analysts: Images, Containers and a Small Local Setup
Learn Docker images, containers, ports and storage through a small local report preview. Mount files read-only, check the setup and remove the container.
Read articleScope, Budget and Change Requests in Analytics Projects
Define analytics project scope, estimate effort and assess change requests. Use a worked budget example to make assumptions, dependencies and decisions clear.
Read articleClient Updates That Explain Progress, Problems and Next Steps
Write useful analytics client updates. Explain verified progress, blockers and decisions, listen before advising, and turn meetings into clear next steps.
Read articlePresenting Analytics Findings So Other People Can Act
Present analytics findings with clear evidence, limits and next steps. Use a worked form example to help clients and designers choose a practical action.
Read articleRunning an Analytics Discovery Call That Produces a Clear Brief
Run an analytics discovery call that ends with a clear brief. Ask about decisions, evidence, access and constraints, then agree on scope, owners and next steps.
Read articleFinding the Website Problem Worth Fixing First
Choose which website problem to fix first. Compare affected tasks, severity, evidence and effort, using a worked example that separates blockers from assumptions.
Read articleHow to Frame an Analytics Question Before Opening a Dashboard
Frame an analytics question before opening a dashboard. Define the population, comparison and possible explanations, then choose evidence that supports a decision.
Read articleChoosing KPIs: Outputs, Outcomes and Business Impact
Choose KPIs that support real decisions. Separate outputs, outcomes and business impact, check a lead-generation example, and define targets with safeguards.
Read articleHow to Assess Analytics Data Quality
Assess analytics data quality against a real decision: set an error tolerance, check completeness, validity, consistency and timeliness, then reach a verdict.
Read articleBuilding a Small GA4 Data API Reporting Script
Build a small Python report with the GA4 Data API: fixed scope, full pagination, and checks for sampling, missing days and (other) rows before saving a CSV.
Read articleJSON for Analysts: Reading, Parsing and Checking Data
Read JSON in analytics integrations. Separate text from objects, parse safely, check required fields, and understand what changes when data is serialised.
Read articleWorking with Arrays and Strings in Analytics JavaScript
Work with arrays and strings in analytics JavaScript. Prepare reporting values, preserve IDs and item order, and avoid changing the original application data.
Read articleBuilding a Measurement Strategy Around Business Decisions
Build a measurement strategy from one business decision. Define evidence, data owners and limits, then use a worked checkout example to plan what to measure.
Read articleThe Second Order Problem: Using RFM to Ask Better Questions
RFM scores can hide what matters when most customers have one order. A worked example shows how to turn segments into better second purchase questions.
Read articleMeasuring Customer Retention: Cohorts and Data Requirements
Build a customer retention cohort table from order data, define a returning customer, avoid common calculation traps, and learn when GA4 is not enough.
Read articleEvaluating a Marketing Campaign Beyond Platform ROAS
A worked example that turns platform ROAS into campaign profit, with VAT, returns, margin, all campaign costs, incremental orders and measurement limits.
Read articleExplaining an Experiment Result to a Client
How to explain an A/B test result to a client: effect, uncertainty and the next decision, with a checked example and wording for a win, loss or unclear result.
Read articleDesigning an A/B Test You Can Actually Evaluate
Plan an A/B test that can give a usable answer: write the hypothesis, pick one metric, calculate sample size, fix the split and check for sample ratio mismatch.
Read articleStatistical Hypotheses and P-values for Practical A/B Tests
Learn what a p-value means in an A/B test, when a one-sided test is valid, and how to run a two-proportion z-test by hand with a checked worked example.
Read articleCorrelation, Variation and Uncertainty in Everyday Analytics
A change or a correlation between two metrics does not show a cause. Worked examples show how to check week-to-week noise, uncertainty and shared causes.
Read articleMeasuring Feature Adoption Without Mistaking Clicks for Value
Define what counts as using a website feature, separate a visit, a use and an outcome, and test adoption with a worked funnel and a fair comparison group.
Read articleSession Recordings: How to Find a Problem Worth Investigating
Choose session recordings with a sampling plan, separate observation from interpretation, keep useful notes, and handle Clarity masking and consent correctly.
Read articleReading Heatmaps Without Inventing User Intent
A heatmap shows where clicks and scrolling happened, not why. Learn what Clarity maps measure, where they mislead and how to verify a finding before acting.
Read articlePivot Tables for Analysts: From Raw Rows to a Useful Answer
Use a pivot table to answer a real sales question: prepare the rows, check the grain and totals, avoid counting lines as orders, then add a simple chart.
Read articleSpreadsheet Skills That Still Matter for Analysts
Reconcile GA4 data with shop orders in a spreadsheet: check imports, clean IDs, use XLOOKUP, highlight differences and chart the one number that matters.
Read articleData Studio Parameters: Build Scenarios Without Changing Actuals
Build a Data Studio scenario with a numeric parameter. Keep actual revenue separate, check percentage units and aggregation, and test controls before sharing.
Read articleData Studio Data Blending: When the Numbers Stop Adding Up
Check Data Studio blends before trusting their totals. Align row grain and join keys, trace repeated targets, and test missing matches, dates and filters.
Read articleBuilding a Data Studio Dashboard Around a Decision
Build a Data Studio (formerly Looker Studio) dashboard from one recurring decision, choosing data sources, charts, filters and layout that help someone act.
Read articleCalling an API: A Practical Request-and-Response Walkthrough
A practical API walkthrough with one cURL and one Python example: send an authenticated request, read the response, and handle errors without exposing tokens.
Read articleGA4 Data API or BigQuery: Which Fits Your Question?
Choose between the GA4 Data API and BigQuery by the data your question needs, the limits it will hit, and what the resulting number means for your decision.
Read articleSQL Joins: Why Your Revenue Doubled After Joining Tables
A join can double revenue without any error. Learn how cardinality and join types multiply rows, how to check row counts, and how to sum at the right level.
Read articleSQL Aggregations for Analysts: Counts, Groups and Common Mistakes
Learn GROUP BY, COUNT and SUM on the GA4 BigQuery export, and how thinking about data grain prevents double counting in users, sessions and revenue totals.
Read articleYour First Useful SQL Query on Analytics Data
Build one SQL query on the GA4 BigQuery export with SELECT, WHERE and DISTINCT, check its scope and cost with a dry run, then test the answer before sharing.
Read articleGA4 to BigQuery: Choosing and Checking Your Export
Set up the GA4 BigQuery export with fewer regrets: linking steps, daily or streaming, region and limits, events to exclude, and how to check the data arrives.
Read articleWhy Google Ads, Meta and GA4 Report Different Conversions
Google Ads, Meta and GA4 rarely match. Use this method to align definitions, dates and windows, explain the gap, and choose the right number for each question.
Read articleAttribution Models: What They Explain and What They Cannot Prove
Attribution models split credit across observed journeys. Learn what GA4 offers today, how lookback windows work, and when you need an incrementality test.
Read articleUTM Parameters: A Naming Convention That Holds Up
Build a UTM naming convention that keeps GA4 channels clean. See which values break channel grouping, how to keep a link log and when not to use UTMs at all.
Read articleImplementing and Validating GA4 E-commerce Tracking
Validate GA4 e-commerce tracking from data layer to order system. Test the paths that break, find the cause of common faults and reconcile purchases with orders.
Read articlePlanning GA4 E-commerce Events Before Implementation
Plan GA4 e-commerce tracking before you build it. Choose events, map the real checkout, define products and revenue, and write a specification developers can use.
Read articleCookies, Local Storage and Session Storage in Analytics
Choose between cookies, local storage and session storage for analytics. Four questions, a worked campaign example, browser limits and how to test the choice.
Read articleTracking Single-Page Applications Without Duplicate Events
Track single-page applications in GTM and GA4 without double counting. Choose one page view source, keep values current, stop stacked listeners and test a journey.
Read articleSetting Up CookieHub with GTM: A Practical Verification Guide
Set up CookieHub in Google Tag Manager and test it properly. Check first load, acceptance, rejection and withdrawal in Tag Assistant and in network requests.
Read articleMaintaining a GTM Container Without Losing Control
Keep a GTM container understandable as it grows. Check each request first, change as little as possible, name items clearly, and remove old tags with evidence.
Read articleGA4 Users, Sessions and Engagement: What the Metrics Mean
Understand GA4 users, sessions and engagement rate, and avoid common mistakes: adding users across days, averaging rates and treating a bounce as a failure.
Read articleWhat Useful Tracking Documentation Should Contain
Write tracking documentation people actually use. See which details each event needs, a worked event record, and how to keep it matched to your GTM container.
Read articleWhy GA4 Reports and Raw Data Can Differ
GA4 reports and BigQuery rarely match exactly. Learn the usual causes, from modelling and Google signals to time zones, and how to tell which gap is a problem.
Read articleGTM Workspaces and Versions: Publishing Changes Safely
Use GTM workspaces and versions to keep changes separate, resolve conflicts and roll back correctly. Learn why Live and Latest can differ, and when it matters.
Read articleGA4 Explorations: Segments, Funnels and Useful Questions
Use GA4 Explorations to answer a specific question. Choose between free-form, funnel, path and segment overlap, set the right segment scope and check the result.
Read articleChrome DevTools for Analytics Debugging
Debug analytics tracking in Chrome DevTools. Use the Console, Network and Application panels in one repeatable check, from data layer push to GA4 request.
Read articleJavaScript Event Listeners: What Can Break Your Tracking
Find missing and duplicate tracking caused by JavaScript listeners. Check event propagation, listener cleanup and the difference between clicks and outcomes.
Read articleDebugging GTM with Preview Mode and Container Exports
Find out why a GTM tag fired or stayed silent. Read the selected event in Preview mode, check trigger conditions, and trace dependencies in a container export.
Read articleError Handling in GTM: Separate Tag Failures from Page Errors
Separate GTM tag failures, JavaScript errors and application outcomes. Learn which monitor can see each failure and how to test it before trusting the data.
Read articleCSS Selectors for Tracking: Choosing a Reliable Target
Choose reliable CSS selectors for analytics tracking. Check match counts, nested click targets and layout changes before using a selector in Google Tag Manager.
Read articleConditions and Loops in Analytics JavaScript
Use conditions and loops to process analytics items. Separate invalid data from excluded items, preserve IDs, and check the result before sending an event.
Read articleJavaScript Functions for Analysts: Inputs, Outputs and Scope
Understand JavaScript functions through an analytics transformation. Define inputs, returned values and scope, then check the function before using it in GTM.
Read articleJavaScript Data Types and Variables for Analytics Work
Understand JavaScript types and variables through analytics examples. Preserve IDs, convert numbers, handle Boolean values and define checks for missing data.
Read articleHow to Check Whether Your Analytics Tracking Works
Check analytics tracking from website action to GA4 receipt. Use a repeatable test to find missing parameters, duplicate events and misleading tag firing results.
Read articleSetting Up GA4: The Decisions to Make Before Collecting Data
Set up GA4 around the questions you need to answer. Choose streams, events, retention, filters and custom dimensions with a practical enquiry tracking example.
Read articleHow GA4 Collects Data: Events, Parameters and Reporting
Understand how GA4 turns website events and parameters into reports. Follow a worked example to separate event counts, reporting fields and business meaning.
Read articleGTM Tag Timing: Initialization, DOM Ready and Window Loaded
Choose GTM triggers by the data a tag needs. Compare Initialization, DOM Ready and Window Loaded, then diagnose late application data with a practical example.
Read articleGoogle Tag Manager Explained: Tags, Triggers and Variables
Learn how GTM tags, triggers and variables work together. Follow a CSV export example, check the configuration and find which component needs a change.
Read articleCan “Don’t Make Things Up” Reduce AI Hallucinations? I Tested It
I tested a popular anti-hallucination prompt on five AI models. On hard questions it cut invented claims and answers. On everyday tasks it mostly changed tone.
Read articleHTTP Requests Explained for Web Analysts
Read HTTP requests in Chrome DevTools: check methods, headers, payloads and status codes, and distinguish a successful request from correct analytics data.
Read articleHow Websites Work: The Parts an Analyst Needs to Understand
Learn how browsers, servers, HTML, CSS and JavaScript work together, then use a practical form check to separate website failures from measurement problems.
Read articleWhen GA4 Says Almost Every Buyer Is New
When GA4 shows total and first-time purchasers as nearly the same line, check whether customers really buy once or GA4 fails to recognize returning buyers.
Read articleThe Data Layer Explained: What Analysts Need to Understand
Understand the data layer in GTM, distinguish website events from analytics hits, and follow a practical check from a form action to a recorded GA4 event.
Read articleThe Value of an Analyst Is Changing
How AI could shift analytics toward forecasting, increase pressure on billable hours, and make business understanding and judgment more valuable to clients.
Read articleWhy Better Marketing ROI Can Mean Less Growth
Learn why higher marketing ROI can accompany lower growth, how to apply the 60:40 budget guidance, and how experiments estimate the orders campaigns add.
Read articleWhich AI Companies Use Watermarking? A Guide for Copywriters and Students
AI watermarking explained for copywriters and students: which companies use SynthID, what detectors can tell you, and what matters for SEO and assignments.
Read articleWhat Even Is Query Fan-Out?
Query fan-out turns one question into several searches. Learn how it works, what it means for website content, and how to measure useful results for your business.
Read articleHow to Interpret Google Search Console Metrics in an Analysis
Learn how to interpret Google Search Console metrics, assess indexing issues, and use impressions and average position to guide practical website analysis.
Read articleWhat Are Website Cookies? The Basics You Need to Know
Learn what website cookies are, how they work, and the difference between first-party and third-party cookies, with Google Analytics as a practical example.
Read articleDouble Diamond Design Process: The Four Phases Explained
Understand the Double Diamond design process, what happens in each phase, and how solving the right problem differs from building a solution that works well.
Read articleI stopped typing to AI. Then I moved to Linux.
My honest experience with Wispr Flow, Vibe Typer, and Vocalinux on Ubuntu, including mixed-language dictation and the tradeoffs of local voice AI tools.
Read articleHow I Accidentally Cost a Client €1,700 in BigQuery
A real BigQuery cost post-mortem: how broad queries and a raw-table dashboard produced a €1,700 bill, plus six guardrails to prevent it.
Read articleWhich Consent Signals Should You Use for Additional Consent Checks in GTM?
A plain guide to Google Consent Mode’s seven signals, GTM Additional Consent Checks, and why adding extra checks to Google tags can break tracking.
Read articleCan You Track Google AI Mode in GA4? The Honest Answer Is Still No
Google AI Mode and AI Overviews stay inside Organic Search in GA4. Here is what the new AI Assistant channel and Search Console report actually show.
Read articleWhy are impressions a bad metric?
Impressions and average position look important in Search Console, but they hide more than they show. Here's why I stopped trusting them, and what to track instead.
Read articleHow AI content detectors like ZeroGPT actually work, and why I ignore their scores
AI detectors like ZeroGPT score text as human or machine using perplexity and burstiness. Here's why I ignore that score, and what to optimize for instead.
Read articleT3 Code Review: Why It Replaced Codex in My Workflow
My hands-on T3 Code review: multi-project workflows, T3 Connect, computer use, subscription support, Linux setup, and where Codex still wins.
Read articleMicrosoft Clarity GTM Template: Why Community Beats Official
Official vs community Microsoft Clarity GTM templates: custom events, Consent Mode v2, sandboxing, maintenance, and when each option makes sense.
Read articleGA4 + BigQuery: the raw data your e-shop is already leaving on the table
GA4's reports quietly hide, sample and cap your data. Here's why an e-shop should export raw event data to BigQuery, what you actually gain, and how to start.
Read articleREST APIs for Analysts: The Part You Actually Need to Know
You don't build REST APIs as an analyst, but you call them all day. Here's the practical REST literacy that pays off in GA4, connectors and dashboards.
Read articleAI Search KPIs: What to Measure for AIO and GEO Success
A three-tier AI search KPI framework: organic users and conversions, content and ranking growth, and AI citation signals.
Read articleKISK (+ FI) First Two Semesters Reflection
Reflecting on my first two semesters and courses taken after moving from FI to KISK at Masaryk University.
Read articleMe & Tazavec: 5 Things I Learned From My Failed AI App
Over a year ago, I shipped my first solo app on Google Play. It was called Tazavec. I managed to earn €0.20. Here's my reflection on that journey and lessons that I am taking away.
Read articleT3 Chat Review: Excellent UX, but I Still Cancelled
My honest T3 Chat review after one month: excellent UX and model switching, but I cancelled because persistent memory was missing.
Read articleReflection on My University Studies as I Am in the First Year Again
After two years at the FI MUNI, I walked away and started over at KISK. This is the story of discovering that sometimes the "wrong" path leads you exactly where you need to be.
Read articleHow to Connect a Smart Rubik’s Cube to Flutter with BLE and Unity
Flutter & Smart Rubik’s Cubes: All you need to know Hey, I’m Branislav! A Flutter developer with over 2 years of experience in the field. Last year, for my final year school project, I decided to …
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