Case-based Excel training

Learn to see what Excel experts see.

Ten realistic spreadsheets that went quietly wrong. Inspect each one, decide what you'd do, then compare your read with an expert's.

Find your level
  1. 1Scan
  2. 2Decide
  3. 3Compare & debrief

Case library

Start with case 1, or pick one that feels a little too hard. Use the View tools the way an expert would. Knowing when to reach for them is part of the lesson.Start with case 1, or choose your level below.

Find your level

People move up by changing what they look at: from single cells, to patterns across cells, to how the whole sheet is built. Pick the rung that honestly describes you to get a stretch set of three cases.

Review & retention

Skill fades fastest right after you stop practicing. Finished cases come back at growing intervals, and mixed drills shuffle concepts so you practice recognizing which problem you're facing. Progress is saved only in this browser.

Part 2

Reference

The ideas behind the cases, the rules they teach, and how to build your own library.

Concept web

Each concept shows up in several cases, in a different form each time. A concept you've met in four situations is one you can use in a fifth. Click a column heading to filter the case library to that concept.Open a concept to see the cases that use it.

    Field rules

    Short enough to remember under pressure. They stick once you've seen each one save you in a case, so every rule links to the cases that teach it.

      For team leads: build your own case library

      Your team's best training material is already in the shared drive: the sheets that went wrong, and the person who noticed. Here's a lightweight way to capture what they know before they move on.

      1. Find experts by asking who people go to.Ask: "When a spreadsheet looks wrong, who do you send it to?" The names that keep coming up are your experts, whatever their titles.
      2. Interview them about incidents, not tips.One 45-minute conversation each. Listen for cues (what they noticed) and moves (what they did next).
        • "Tell me about a mistake you caught that nobody else noticed. What tipped you off?"
        • "When someone hands you a sheet you didn't build, what do you look at in the first minute?"
        • "What would a new hire miss there, and why?"
        • "Have you ever been fooled? What did the sheet look like?"
      3. Turn each incident into a case.Strip confidential data, keep the structure, and freeze it just before the expert noticed.
      4. Run cases as a group exercise.Everyone commits privately to their flags and their move. Compare around the table, with the expert speaking last.
      5. Debrief every real failure the same way.What went wrong? What will we do differently? How will we know it's working? Then file it as a new case.

      Case template

      ## Case: <short memorable title>
Level: Apprentice | Journeyman | Expert
Concepts: <e.g. silent errors, ranges that don't grow>

### Situation (what the learner is told)
Who sent it, what it's for, the deadline, what's riding on it.

### The sheet (frozen just before the expert noticed)
Attach a de-identified workbook or paste a small grid.

### Scan prompt
"Flag every cell you'd question before this goes out."

### What the expert saw (cues)
- <cell>: <what looked off and why it mattered>

### Decision point
3–4 plausible options, including the tempting wrong one.

### The expert's move and reasoning

### The belief that hides this problem
Belief: "…"   Reality: "…"

### Where else this shows up

      Why this page works the way it does

      Each design choice comes from research on accelerated expertise. The honest caveat applies here too: these methods speed up proficiency. Mastery still takes years of real problems.