Finalidad y Objetivos de la Investigación 1 Finalidad

The data dimensions of the derived information in location-sharing scenarios has statistically significant impact on users’ willingness to share (Pearson Chi-Square= 22.72, p<0.0001). In particular, there is a moderate positive correlation between the participants’ sharing attitude and the data dimension of the extracted information (Spearman’s rho=0.53, p<0.0001), which means having more data dimensions involved in a given location-sharing action increases users’ concern about location privacy and reduces their willingness to share.

When examining the relationship between user perceptions across all data dimension combina- tions using the logistic regression, participants presented with Spatial scenarios were most likely to share their location, and those presented with Spatial-Social scenarios were more likely to share their location than participants in Spatial-Social-Temporal scenarios, as expected. This finding suggests that participants exposed to scenarios that reveal more data dimensions, and hence personal information, were more likely to express privacy concerns than those in less revealing dimension scenarios. This is indicated in participants’ justifications of why they were reluctant to share their location, where most of them refer to privacy and safety issues, saying, for example, “I may not want people to know all of my personal business about where I am and what I’m doing” and “I wouldn’t share my location in any place where my personal privacy or safety concerns were an issue”.

Participants in the Spatial scenarios are the least concerned about their privacy (Maybe 25.1%:, No: 28.8%), whereas privacy concerns increase for the Spatial-Social scenarios (Maybe 27.7%:, No: 29.6%) and the highest concern rate is shown in Spatial-Social-Temporal scenarios (Maybe 27%:, No: 33.2%). Participants who answered maybe or no to locations sharing in Spatial- Social scenarios were more specific in explaining their choices by indicating particular concern with identifying places that are frequently visited, where they said “I would not share anything too personal, like places I frequent that are in my neighbourhood” and “If it’s a place that I commonly go, then I would not share”. Similarly, participants who refused or hesitated to share locations in Spatial-Social-Temporal scenarios justified their attitude by referring to their concerns about others finding their movements patterns and the consequences of such inference, saying, for example, “I am concerned about my safety. Some people could see the pattern of my whereabouts, and use that information to stalk me or my friend”, “If things are routine, that is giving someone your schedule and they could track you and get to you if they wanted to”, and “Because there are some places you just do not need to let others know where the location is. These days people could try to come to your home and rape you, murder you, or even kidnap

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you”. Some were worried about their privacy regarding absence from their personal places, such as their home, as they explained, “Sharing my location for places I visit on a regular basis advertises that I am not at home on those days and times” and “I would not let anyone know where I go on a regular basis. This is a good way to get your home robbed”.

6.3.1.1 Sensitivity of Location-sharing Scenarios

The sensitivity factor of the location as well as what information it reveals was considered when designed the location-sharing scenarios, as this has the potential to influence how people react toward sharing a given location. Locations that are categorised as sensitive are based on privacy acts, and those referred to as personal mainly include home locations (as discussed in the data dimension aspect). Generally, observing the sensitivity of location and the potentially inferred personal information across all data dimension combinations has a statistically significant effect on users’ willingness to share (Pearson Chi-Square= 729.903, p<0.0001). A positive correlation was found between the participants’ attitude level and the sensitivity of the derived information (Spearman’s rho=0.312, p<0.0001). This implies that users’ location sharing decision and hence location privacy concerns are influenced by the sensitivity of the place or associated information. As expected, participants are the most likely to share their location in non-sensitive scenarios (Yes: 58.4%, Maybe: 27%, No: 14.6%).

However, users’ willingness to share decreases significantly (by 31%) when sensitivity in- creases, indicating that participants are the most concerned about their privacy and least likely to share their personal locations (i.e. their home) (Yes: 27.4%, Maybe: 21.9%, No: 50.7%), followed by their sensitive locations (Yes: 33.2%, Maybe: 27.7%, No: 39.1%). Participants’ justification for their reluctance to share also suggested that they are willing to share public or interesting locations but not private or sensitive ones. They explained this saying “Shar- ing location information for public places is mostly OK with me but sharing personal location information related to religion, political affiliation or a friend’s house via location info is some- thing I try not to do” and “I really wouldn’t want to share medical location places or anything having to do with my culture, faith or home. Those are private issues that I do not mention on social networks”. Several participants mentioned that they would hesitate to share their loca- tions if “they’re boring” or “they are not of interest to most people”. Observing participants’ justifications shows that they consider the location sensitivity in the first place, and some also take into account the interestingness or usefulness factors of the location to others.

Examining the participants sharing attitude individually towards the categories of sensitive in- formation showed that the top two information categories that participants both hesitated and denied sharing are health (Maybe:22%, No:55%) followed by home(Maybe:27%, No: 51%) as

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illustrated in Figure 6.4. The third and fourth categories that participants refused to share are religion and political views (38% and 35%, respectively).

Figure 6.4: Sharing decisions for sensitive and personal places .

6.3.1.2 Sharing Behaviour When being with friends

Whether a user is with a friend can also influence their attitude toward location sharing. The possibility of a friend’s presence in a place with a user is a sub-factor of the social dimension. We captured its impact by presenting approximately the same number of scenarios where 1) a user is alone at a place, and 2) being with a friend whenever the social dimension is involved . An overview of participants’ sharing decisions when at a place with a friend, across all data dimension combinations, showed that it has a statistically significant impact on their willingness to share the location that their friends are tagged in, and hence their privacy perceptions (Pearson Chi-Square= 46.363, p<0.0001). This association has a positive correlation between sharing attitude and whether the user is with a friend (Spearman’s rho=0.082, p<0.0001). Participants are less likely to share their location if they are with a friend than when at a place themselves (38% said yes when with a friend, compared to 46% when alone).

The reasons for this difference in attitude are explained by participants to be mainly because they think the information is sensitive and needs to be protected, or they have to seek their friend’s permission before sharing, as they said, “To protect the privacy of other people I was with or visiting” and “If I do tag friends, I like to ask their permission first”. Examining parti- cipants’ willingness to share their location when with a close friend or just a friend from a social network connection, revealed that it is significantly associated with participants’ sharing attitude (Pearson Chi-Square= 1.04.255, p<0.0001). Participants are less willing to share their location when they are with a close friend (No: 38%) than when with an acquaintance (No: 21%), as demonstrated in Figure 7.7. This might be because a user can be with a close friend in any Spatial-Social and Spatial-Social-temporal scenario whether the visit to a place is occasional or

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routine. Hence, the scenario can be more privacy-threatening, which makes the participant less willing to share. It can also be because participants want to protect the privacy of their close friend. Interestingly, some participants who selected not to share their location with a friend from a social network justified their choice by saying, “Me along with my close friend, loca- tion sharing is ok, but there is no point to share the information of me with an unknown guy to others” and “I don’t know Jack that much, so tagging him would be weird”.

Figure 6.5: Sharing decisions when with a friend categorised by their closeness to user.