Customer acquisition cost and payback: how much you can spend to grow
A plain-English walkthrough of customer acquisition cost and payback period, and how the two numbers together tell you whether your growth spending is actually safe.
Xavier Fok
The North Star Metric: Picking the One Number That Runs Your Business
A plain-English guide to finding your north star metric: the one number that shows whether customers are getting real value, how to find it in your own data, and the mistakes that turn it into a number you game instead of grow.
Joining two datasets without quietly corrupting both
A join against a table I assumed had one row per port left my total data figure about 40% too high for eleven days. Two row counts would have caught it in a second.
Statistical Significance in Plain English: When an A/B Test Is Real
A plain-English breakdown of statistical significance, p-values, and sample size, explained with a coin flip instead of a formula, for anyone testing changes in a small business.
A/B testing for solo founders: how to run one without fooling yourself
A plain-English guide to running an honest A/B test on small traffic, and the specific ways solo founders trick themselves into calling a coin flip a win.
The dataset you can still understand in a year
Fourteen months on I can still open the file, just not read it: a column called status holding three values I can no longer name. Six lines of plain text beside a dataset is what keeps it usable.
Cohort Analysis for Beginners: The One Chart That Explains Your Business
A plain-English guide to building a cohort retention table by hand, why blended churn numbers hide real trends, and how to read the shape of a cohort curve.
Customer Lifetime Value Explained (And How Not to Fool Yourself With It)
A plain-English walkthrough of customer lifetime value: the formula, a worked example, margin adjustments, the CAC ratio, payback period, and the common ways the number gets misused.
How to read your own dashboard without fooling yourself
A chart can change what it appears to say without a single number changing underneath it. The axis, the smoothing, the colour and the missing denominator are all decisions somebody made, and for your own dashboard that somebody is you.
MRR vs ARR: What Each Number Actually Tells a Solo Founder
A plain-English guide to monthly recurring revenue and annual recurring revenue: what each one measures, why ARR isn’t just MRR times twelve, and when to trust which number.