profile 2 profile 3 familia familiar similar profile similar profile similar profile similar profile high rating overlap high rating overlap low rating overlap low rating overlap profile 5 profile 6 profile 7 profile 8 unfamiliar dissimilar profile dissimilar profile dissimilar profile dissimilar profile high rating overlap high rating overlap-low rating overlap low rating overlap Fig 3 Recommender profiles providing any fictitious reviews or synopses was to →- profile choser inimise noise through a possible participant bias towards any film based on the films properties. Each recommendation pair was a forced choice, thus the dependent variable was which film the participant 1。6号 would choose and in turn which recommender they would trust (see the screenshot in Fig 4) 0.4 OMeM.mt出 serbia Eagles wing Oscar winner. 34. Film Bult.24 profile number Fig 5 Profile choice ratios/trust rating significant influence of profile similarity and rating How cmntldest are you b te reo Figure 6 shows the above trend mapped out with the individual profile characteristics Fig 4 Film recommendation Overall profile similarity and high rating overlap had In addition to the actual choice we recorded a an effect on the choice of which recommender to trust confidence rating on a likert scale from l to 5 for each choice Participants rated the same profiles in terms of trust phase 4 of the experiment. Further. we examined the ratio of the number of times a particular profile was chosen and the number of Interestingly, the trend for the trust ratings is the times a profile was seen(choice ratio same as the one for the profiles chosen, except for profiles 7 and 8. Here participants trusted the familiar 3.2.5 Results -overall profiles chosen profile more, whereas they chose the unfamiliar one more often Figure 5 shows the overall trend of choice ratio, as wel as how these profiles were rated in the end in terms of trust 3.2.6 Individual variable analysis Since in each condition recommenders differed in one Trust was elicited through a Likert scale(1-5)in characteristic, while the other characteristics were kept phase 4 in the post-study questionnaire It is interesting constant it is worth examining the independent to note the trend shown in the graph in Fig 5. When variables individually within each condition type. the mapped against profile characteristics, it points to a results are summarised below and detailed in Fig 7 BT Technology Journal. Vol 24 No 3 July 2006‘Knowing me, knowing you’ — using profiles and social networking to improve recommender systems 92 BT Technology Journal • Vol 24 No 3 • July 2006 providing any fictitious reviews or synopses was to minimise noise through a possible participant bias towards any film based on the film’s properties. Each recommendation pair was a forced choice, thus the dependent variable was which film the participant would choose and in turn which recommender they would trust (see the screenshot in Fig 4). In addition to the actual choice, we recorded a confidence rating on a Likert scale from 1 to 5 for each choice. Further, we examined the ratio of the number of times a particular profile was chosen and the number of times a profile was seen (choice ratio). 3.2.5 Results — overall profiles chosen Figure 5 shows the overall trend of choice ratio, as well as how these profiles were rated in the end in terms of trust. Trust was elicited through a Likert scale (1—5) in phase 4 in the post-study questionnaire. It is interesting to note the trend shown in the graph in Fig 5. When mapped against profile characteristics, it points to a significant influence of profile similarity and rating overlap. Figure 6 shows the above trend mapped out with the individual profile characteristics. Overall profile similarity and high rating overlap had an effect on the choice of which recommender to trust. Participants rated the same profiles in terms of trust in phase 4 of the experiment. Interestingly, the trend for the trust ratings is the same as the one for the profiles chosen, except for profiles 7 and 8. Here participants trusted the familiar profile more, whereas they chose the unfamiliar one more often. 3.2.6 Individual variable analysis Since in each condition recommenders differed in one characteristic, while the other characteristics were kept constant, it is worth examining the independent variables individually within each condition type. The results are summarised below and detailed in Fig 7. Fig 4 Film recommendation. Fig 3 Recommender profiles. profile 1 – familiar – similar profile – high rating overlap profile 2 – unfamiliar – similar profile – high rating overlap profile 3 – familiar – similar profile – low rating overlap profile 4 – unfamiliar – similar profile – low rating overlap profile 5 – familiar – dissimilar profile – high rating overlap profile 6 – unfamiliar – dissimilar profile – high rating overlap profile 7 – familiar – dissimilar profile – low rating overlap profile 8 – unfamiliar – dissimilar profile – low rating overlap 0 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 1 2 5 3 4 6 8 7 trust + profile chosen ratio profile number profile chosen trust Fig 5 Profile choice ratios/trust rating