Guides
How spreadsheets go wrong, and how to tell. Useful whether or not you ever use this product.
- Guides
- 15
- Each answers
- one question
- Tool required
- none
- 6 min read
Why two people get different totals from the same spreadsheet.
It is almost never arithmetic. It is nearly always one of four structural problems, and each leaves a signature you can look for.
- 7 min read
How to tell a real finding from a coincidence.
Most findings that fall apart do so for one of four reasons, and all four can be checked in minutes.
- 5 min read
Five things to check before you trust a dashboard.
A dashboard is a set of decisions someone made and then hid. These are the five worth surfacing before you act on one.
- 6 min read
Finding duplicates that Remove Duplicates will not find.
The built-in tool compares cells. Real duplicates disagree in every field, which is exactly why they survived.
- 7 min read
Why Excel changes your numbers without telling you.
Four conversions happen on open, none of them warns you, and all four are irreversible once you save.
- 6 min read
Comparing two versions of a spreadsheet without drowning in false changes.
Three things break a file comparison, and all three make it report far more changes than happened, or far fewer.
- 6 min read
Dates in more than one format, and why it is worse than it looks.
A date column in two formats silently misplaces rows in every period comparison, and about a third of them cannot be recovered at all.
- 5 min read
Why your CSV opens as one column, and what that means.
The single most common CSV complaint has nothing to do with the file, and the second most common one is invisible until somebody searches for a customer.
- 5 min read
Numbers stored as text, and the total that is quietly short.
The most dangerous data problem is the one whose symptom is a number that looks about right.
- 6 min read
Joining two spreadsheets, and the match rate nobody reports.
The join usually works. What goes wrong is that nobody checks how much of it worked.
- 5 min read
When the average describes nobody.
The mean is the right answer to a narrower question than most people are asking when they compute one.
- 6 min read
Six ways a chart misleads without containing a false number.
Almost every misleading chart contains only true numbers. The misleading part is the encoding.
- 5 min read
The data dictionary, and why inheriting a file without one costs a week.
The cheapest document in analytics to produce, and the one whose absence causes the most repeated work.
- 7 min read
Analysing survey results without measuring who answered.
Sample size does not fix a systematic absence, and it is the absence that breaks most survey conclusions.
- 5 min read
Why two dashboards give different numbers for the same thing.
Two people are usually both right about a number, and disagreeing about which number it is.