Appreciation Index The AI or Appreciation Index is a statistical representation of the amount of enjoyment the audience derived from a particular episode of television . Since " Rose " , it has been the method for measuring the tastes of the audience . Different methods were used during the 1963 version of the programme , and so BBC Wales AI scores are not compatible with audience research numbers given in the past , known until around 1981 as the Reaction Index . Modern measurement . A 21st century AI score is calculated using a small but representative group of viewers . This sample will watch a program and then rate the program on a scale of one to ten . The scores are then averaged and multiplied by ten . Hence , an AI of 67 means that 6 . 7 was the simple mean of all responses . Scores of 85 or better are rare , and thus considered " excellent " . Scores below 60 are considered " poor " . Scores for every episode of the BBC Wales version of the program — save " The End of the World " , " Love & Monsters " and " Sleep No More " — have been 80 or above . Every story from " Smith and Jones " to " Victory of the Daleks " scored at least an 85 — a three - year run of the programme ' s most consistent and highest AI performances . The highest - ever AI for a " Doctor Who " episode was a 91 , received by both " The Stolen Earth " and " Journey ' s End " . History . Determining " appreciation " was the original method for registering the success or failure of radio and television programs in Britain . It has been employed by the BBC , in some form , since 1936 . With the advent of commercial television , however , advertisers wanted to know " how many " people were watching . Ratings — a measure of the raw number of viewers in front of television sets — supplanted the AI as the primary measure of televised success . However , as the BBC is not a commercial enterprise , the AI still retains importance in determining the fate of television programs on the networks of the BBC . The Reaction Index . Audience research was done differently in the past . Until 1981 , the BBC performed their own internal research . It was carried out by the Audience Research Department , a fairly large branch of the BBC that had numerous field workers who actually went out into the country to personally question viewers and / or collect written surveys . At least initially , reactions were measured with small samples of around 1000 people . The first episode ' s RI was calculated from a tiny 124 sample size , because only 12 % of the " full " sample of about 1030 — called a " Viewing Panel " in internal documents — watched " Doctor Who " on 23 November 1963 . They gave it a mark from a five - point scale , as follows : This then allowed the calculation of an RI of 63 , which was between the then - current averages of 62 for drama and 64 for children ' s programmes . BARB era . For the balance of the so - called " classic series " , it was moved to a non - profit organisation called the Broadcasters ' Audience Research Board or BARB , which was funded by all broadcasters . During this time , respondents were asked to record a number between 0 and 6 for each programme they watched , with the following meanings : Thus , during most of the John Nathan - Turner era , an AI of 65 — a typical score — would have meant " only a little better than " fairly interesting " " . During the 1990s , a number of different scoring systems were tried , but they didn ' t result in significantly different AI results . Eventually , BARB settled on the simple ten point scale that has been in use throughout the BBC Wales era , and which has applied to " Torchwood " and " The Sarah Jane Adventures " alike . BARB continued calculating AIs as late as 2012 . For most episodes of the BBC Wales era until 2012 , the AI reported is that produced by BARB . However , since 2005 , the BBC also received a second , separately - calculated AI score from , a separate organisation that used online surveys . When BARB bowed out , GFK , and its online " Pulse " panel took over entirely . GfK era . Since 2012 , " Doctor Who " AIs have been exclusive collected from a large online sample of some 20 , 000 individuals responding to an online survey . According to this measurement , 81 is the average BBC One AI . The basic response system is the same ten point scale as BARB used , meaning that an AI of 81 corresponds to an average respondent score of 8 . 1 . The online nature of the survey necessarily excludes those without internet access from participating , possibly marginalising the voices of the elderly , the poor , and the technophobes . However , it also allows for more sophisticated weighting of respondents . According to a BBC report , " The daily reporting panel is weighted for age , social grade , sex , presence of children , region and the household digital type on a daily basis to ensure it is representative of the UK as a whole . "