## 5 Interpretation of Results with Respect to Usability
The extrapolated page latency (full page download) is referenced by _PAGE_, the core latency (HTTP request duration) by _CORE_, while requests directed via the Tor network are referenced by _Tor_, and direct requests by _Direct_. The mapping in Figure 10 shows technical measurements of page latency (_i.e._, page loading time) and the resulting cancelation rates of users who are provided with feedback while loading the page. This figure indicates a high increase in user cancelation when sending requests via Tor. The median of page latency via Tor corresponds to a median of 67% cancelation rate, while user frustr \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Type of Cancelation Rate**} & **Direct, Core** & **Tor, Core** & **Direct, Page** & **Tor, Page** \\  & **Latency** & **Latency** & **Latency** & **Latency** \\ \hline Lab with Feedback & – & – & X & X \\ Lab without Feedback & X & X & – & – \\ Stated Direct & X & – & X & – \\ Stated Anonymous & – & X & – & X \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparing Cancelation Rates from User Studies to our Latency Measurements. direct page latency maps to only 2% cancelation. This gap between cancelation rates indicates a critical jump in expected user cancelation when using the Tor network, which we aim to investigate further by our own set of user studies in future work. Moreover, the user cancelation rate follows a saturation curve. Therefore, early user loss (in terms of cancelation rates) caused by latency is massive. Lowering the page latency via Tor by 7 s would decrease the user cancelation rate by 12%. A reduction of Tor-based page latency by 12 s would reduce the cancelation rate by 33%. Hence, an only minimal optimization of the Tor network latency will not gain a substantial effect. Only if the optimization is massive, a real improvement would be made. In Figure 11, a mapping is provided between technical measurements of core latency and the resulting cancelation rates of users who are not provided with feedback while loading the page. This indicates an even higher, disproportionate increase in user cancelation when sending requests via Tor. The median of the core latency via Tor maps to a median of 78% cancelation rate, while user frustration for the median of direct page latency maps to 14% cancelation (lowest measured cancelation rate, we assume an even lower cancelation rate here if cancelation rate data would be more precise). Lowering core latency via Tor by 3 s would decrease user cancelation rate by 17%. A reduction of Tor-based core latency by 8 s would reduce the cancelation rate to the same level as when using a direct connection--of course with the caveat of non-exact measurement data of the laboratory studies for direct access. These results indicate an expected massive gain in user acceptance if Tor network latency is reduced significantly. Both mappings provide a combined line of argument. Their results indicate the same amount of performance improvements necessary for Tor. The results shown in Figures 10 and 11 do not distinguish between user acceptance of anonymous _vs._ non-anonymous browsing because this was not tested in the lab studies we refer to. Figure 12 displays technical measurements of core and page latency using a direct connection, which are mapped to the resulting cancelation rates of users asked for their acceptance of latency during normal  
Figure 11: Core Latency and Cancelation Rate (Lab Experiment without Feedback). Figure 12: Latency and Cancelation Rate for Normal Web Browsing (Survey Statements). browsing (referenced by _Norm_). This mapping indicates that core and page latency of an average direct connection are accepted by more than 96% of the users. Finally, Figure 13 shows the mapping of technical measurements of core and page latency using a connection over Tor to the cancelation rates of users who have been asked for their acceptance of latency while browsing anonymously (referenced by _Anon_).