The ERI readiness index: a number that means something
“Am I ready?” is the question every candidate asks, and a raw percentage of correct answers is a poor reply: acing easy questions does not prepare you for a selective competition. The ERI (Erudiam Readiness Index) is our answer: an index from 0 to 100, per test and overall, designed to be comparable over time and honest about what it measures.
Photo: Daniel Thomas, Unsplash
This page explains exactly how it is computed, what it takes into account and what it does not claim to do.
How the index is computed
The ERI is difficulty-weighted accuracy: a hard question answered correctly weighs more than an easy one, in proportion to its difficulty level. Only questions in the realistic exam format count, over a rolling window of 7, 30 or 90 days: the index reflects your current level, not where you started.
Each test has its own index (verbal, numerical and abstract reasoning, EU knowledge, digital skills), and the overall index combines them weighted by your practice volume: a barely practised test cannot artificially inflate the score. The EUFTE written test, which is not a multiple-choice test, is excluded.
Adapted to your target competition
The same index does not mean the same thing across competitions. If you are aiming for AD 5, the overall index combines the four multiple-choice tests of the competition. If you are aiming for CAST, where the EPSO part of the selection only includes reasoning, the overall index only counts verbal, numerical and abstract reasoning: any practice on other tests is still measured, but does not count towards your CAST readiness.
Find out where you stand in minutes
The free diagnostic test establishes your first index, test by test, and tells you where to start.
Take the diagnostic test
Screenshot of the app.
The cohort percentile, optional and anonymous
Knowing where you stand among other candidates is useful, provided the comparison is honest. The cohort percentile is strictly optional (explicit GDPR consent, off by default) and anonymised by construction: it is computed on aggregated daily snapshots, and no percentile is shown until there are at least 50 comparable profiles in the cohort.
Here too the target matters: per-test percentiles compare all candidates (the reasoning tests are common to every EPSO profile), but a CAST overall index and an AD 5 overall index do not measure the same thing, so we do not compare them to each other.
What the ERI is not
The ERI is not a prediction of success: a competition depends on the level of other candidates, the number of places and the day itself. It is a tool for steering your preparation: it tells you where to focus effort, whether your work is paying off, and how your level changes over time. No score, here or anywhere, replaces the training it measures.