MRCGP AKT statistics and evidence revision

Use this before comparing treatment and control groups.

The difference in absolute risk between two groups.

Tells you how risk changes proportionally, not the absolute benefit.

Lower NNT means fewer patients need treatment for one to benefit.

Higher NNH means harm is less frequent.

Useful for ruling out when a sensitive test is negative.

Useful for ruling in when a specific test is positive.

Depends heavily on prevalence.

Start with interpretation, then formulas

The RCGP data interpretation examples are built around real GP problems: prescribing, referral data, risk communication and patient decisions. Do not only memorise equations.

Practise the table first

For diagnostic test questions, write true positive, false positive, false negative and true negative in the same order every time before calculating sensitivity, specificity, PPV or NPV.

Use audio for repeated exposure

Statistics is easier when the language becomes familiar. AKT Navigator includes a statistics course and over 2 hours of statistics explainer videos in paid access.

How much of the AKT is statistics?

The RCGP describes the AKT as 80% clinical knowledge, 10% evidence-based practice and critical appraisal, and 10% primary care organisation and management. The statistics and data interpretation material sits mainly in that evidence-based practice section.

What statistics formulas do I need for the AKT?

You should be comfortable with absolute risk, relative risk, absolute risk reduction, absolute risk increase, NNT, NNH, sensitivity, specificity, PPV and NPV. You also need to interpret charts, confidence intervals, forest plots and practice-level data.

How do I revise PPV and NPV for the AKT?

Build the 2x2 table first. PPV starts from the positive test results and asks how many are true positives. NPV starts from the negative test results and asks how many are true negatives. Remember that PPV and NPV change with prevalence.

What is the fastest way to improve AKT statistics?

Learn the small set of core formulas, then practise mixed interpretation questions rather than memorising formulas in isolation. Focus on 2x2 tables, absolute versus relative risk, NNT, confidence intervals and chart interpretation.

Is AKT statistics only calculations?

No. The RCGP data interpretation material includes graph reading, prescribing data, confidence intervals, PPV, absolute and relative risk, forest plots, patient risk communication, NNT and NNH. Recent feedback reports also highlight practice chart interpretation and study design terminology.