The Chido journal
Notes from the operations floor
Practical writing on process improvement, Lean Six Sigma and operational capability — written so anyone can follow it, with the maths done properly.
The method · 6 pieces · about this category →
Kaizen means change for the better, done continuously by the people doing the work. Simple idea, powerful maths — and easy to reduce to a suggestion box nobody reads.
1 September 2026 Five questions to ask before your next improvement projectMost improvement projects fail before they start — a symptom mistaken for a problem, a baseline never measured. Five plain questions catch it early.
18 August 2026 The hidden cost of broken processesWaste hides because everyone nearby has adapted to it. Two simple pieces of maths show why it is worse than it looks — and why "everyone at 95% busy" is a disaster.
5 January 2026 Breakthrough vs control — two different jobs, and why most teams only do oneKeeping a process at its current level and moving it to a better one are different jobs needing different tools. Confusing them is why so much effort yields so little.
10 December 2022 What is Lean Six Sigma — and when is it the wrong tool?The method works. The hype around it often does not. What Lean Six Sigma actually promises, in plain English — and where it earns or loses its keep.
17 November 2022 Statistical Process Control — the chart everyone draws and half misuseA control chart answers one question: is this noise, or news? Simple idea, constantly misused. Here is how it works and how it gets abused.
Statistics in practice · 6 pieces · about this category →
The bell curve shows up everywhere for a real reason — and gets wrongly assumed everywhere else. How to enjoy the first and avoid the second.
9 January 2026 Chi-squared worked example — and every place the calculation can quietly go wrongA complete worked test, in plain steps — with the four honesty checks that decide whether the answer deserves to be trusted.
25 February 2023 Why the chi-squared test is right-tailed — and what a too-perfect result meansDisagreement with your theory always pushes the chi-squared number up, never down. Which is why a suspiciously tiny result asks a different question — about the data itself.
25 February 2023 The chi-squared test — what it measures, and the fine print nobody readsA test for counted things: complaints by site, passes by shift. It tells you whether a difference is bigger than chance — and stays silent about whether it matters.
25 February 2023 The beta distribution — the honest way to talk about rates you are unsure ofAsk a team their defect rate and you get one number. Ask how sure they are and the room goes quiet. This is the maths of that missing second answer.
14 December 2022 What is statistics — description, inference, and the gap people fall intoHalf of statistics describes what happened. The other half makes careful guesses about what you did not see. Most mistakes come from mixing the two up.
Data & decisions · 2 pieces · about this category →
The textbook tool for choosing under uncertainty is a weighted average. Right for repeated choices; misleading for one-shots and anything you cannot survive getting wrong.
15 October 2022 Data exploration — why the first hour with the data decides the whole analysisFour datasets, identical statistics, four completely different stories. The case for looking before calculating, in one famous picture.