The Appreciation Index or AI is a measure of how much the audience enjoyed the programme. The score, out of a hundred, is compiled by a specially selected panel of around 5,000 people who go online and rate and comment on programmes.
The score of 85 is around the general average for Doctor Who AIs over the past nine years, and is considered 'excellent'. Flatline achieved the joint highest AI of the series so far - and you can see the AIs for the rest of the series below:
- Mummy on the Orient Express & Flatline - 85
- Into the Dalek & Time Heist - 84
- The Caretaker - 83
- Deep Breath, Robot of Sherwood, Listen & Kill the Moon - 82
[Source: Doctor Who News]