How the Redrock Study works
You play a researcher on a fictional island, working towards one research objective, usually about animals or plants. Redrock has two parts. The study comes first, in three phases: Investigation, Analysis and Report. Six short mini-cases on the same theme follow. Each part opens with an untimed tutorial.
In Investigation you read about a page of text, tables and charts and drag the figures that matter into a research journal. There is no calculator yet. Only about 10 to 15% of the numbers on the page are reported to be needed.
In Analysis an on-screen calculator appears and you answer two to four linked questions, usually three, from the figures you collected. The calculator logs every result unrounded, and you can drag any logged result into an answer box or the next calculation.
In Report you fill the gaps in a written summary, choose a chart type and fill in the chart or table. Once Report opens you cannot go back to Investigation or Analysis.
The mini-cases use their own data, separate from the study and from each other, so a mistake in one does not carry into the next. Answers are either typed numbers or multiple choice, and the calculator is there in almost every case.
How to approach Redrock
Work through the study in this order:
- Read the objective and work out the calculation it implies before you collect anything. That tells you which figures matter.
- In Investigation, collect only the figures that feed that calculation. Rename each journal card so you know what it is later.
- In Analysis, build each answer from the calculator’s logged results instead of retyping rounded numbers. A wrong early answer feeds into every later one, so sense-check each result.
- Before you open Report, check you hold every value the summary will need and know which chart fits the data. There is no way back.
- In the mini-cases, read what is asked before touching the calculator. If you are stuck after about 45 seconds, rule out what the data makes impossible, choose and move on.
Worked example
Objective: find the average nesting success across three heron colonies, weighted by the number of nests. Colony A has 40 nests with 75% success, Colony B has 25 nests with 60% success and Colony C has 35 nests with 80% success. The page also gives each colony’s area and founding year. You do not need those, so leave them out of the journal.
Successful nests: 40 × 0.75 = 30, 25 × 0.60 = 15 and 35 × 0.80 = 28, which makes 73 out of 100 nests. The weighted success rate is 73%. Averaging the three percentages instead gives 71.7%, the wrong answer the question is built to catch.
If the report then asks how far Colony B falls below that average, the gap is 73 - 60 = 13 percentage points, or 13 ÷ 73 = about 17.8% in relative terms. Check which one the blank wants. To compare the three colonies, choose a bar chart; a line chart implies change over time.
Tips for the real Redrock Study
- Check the total length in your invitation email. McKinsey gives it there and nowhere else.
- Read every tutorial fully. They are untimed, so the clock is not running while you learn the screen.
- Revise the difference between percent and percentage points, plus mean, median and mode, weighted averages and simple probability. These are the topics most often reported.
- Know which chart suits which data: bar for comparing categories, line for change over time, pie for parts of one whole, scatter for two variables together, and the stacked versions.
- Type into the calculator with a keyboard numpad if you have one. It is reported to save minutes over clicking.
- Sit it alone on a PC or Mac. McKinsey bans other apps, websites, AI tools, pre-prepared notes and screenshots.
- Never leave a mini-case blank. A reasoned guess can score; a blank cannot.
Practise Redrock on CogniPrep
We split Redrock into four drills, each on its own clock: Investigation (8 minutes), Analysis (8 minutes), Report (6 minutes) and Cases (13 minutes). Together they come to 35 minutes, where the real module runs all four parts on one clock.
Investigation gives you one research brief from a pool of six and scores what you file and what you leave out. Analysis hands you the journal figures and asks three or four chained questions, with a logging calculator and typed answers accepted within 1%. Report supplies the analysis output, and you fill the summary, pick a chart type and populate it. Cases draws six cases from a pool of 30. None of the drills has a Back button, each ends with a score out of 100, and Investigation is free.