# Effective Techniques for Protecting the Privacy of Web Users
## 5 Experimental Results
Consider our case of allow and block tracking, Specificity relates to the ability of PPTs to efficiently block tracking JavaScript programs. In mathematic terms, this can be expressed as:  
\[\text{Specificity (TNR)}=\frac{\text{TN}}{\text{TN}+\text{FP}}\]  
where True Negative (TN) is the number of tracking JavaScript programs that are correctly blocked, False Positive (FP) is the number of functional JavaScript programs that are incorrectly blocked. (Figure 5) illustrate the accuracy of the privacy protection tools based on Sensitivity and Specificity. We considered sensitivity and specificity to help us decide which privacy tool would best identify negative and allow positive JavaScript programs. If correctly identifying positives is more important, then we should choose a privacy tool with higher sensitivity. In contrast, if correctly identifying negatives is more critical, then specificity should be prioritized. Based on the results, we can conclude that PP-Tools' true positive rates vary from 69% to 87%, and true negative rates vary from 68% to 87%. As expected, Ghosteryt has the highest Sensitivity rate of 87% due to allowing most JavaScript programs to run in-page, at  
Figure 5: Shows the ratio between sensitivity and specificity of the PPTs. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**PPTs** & \multicolumn{2}{c}{**Positive Class**} & \multicolumn{2}{c}{**Negative Class**} \\  & \multicolumn{2}{c}{**(Functional jsec)**} & \multicolumn{2}{c}{**(Tracking jsec)**} \\ \hline  & TPR & FPR & TNR & FNR \\ \hline DC & 0.69 & 0.31 & 0.68 & 0.32 \\ \hline GT & 0.87 & 0.13 & 0.84 & 0.16 \\ \hline ABP & 0.82 & 0.18 & 0.73 & 0.27 \\ \hline UB & 0.86 & 0.14 & 0.82 & 0.18 \\ \hline PB & 0.71 & 0.29 & 0.69 & 0.31 \\ \hline NS & 0.80 & 0.20 & 0.87 & 0.13 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of the PPTs with our labeled dataset between allow and block functional (TP, FP), and allow and block tracking (FN, TN). the expense of its poorest Specificity rate. The next best are uBlock, Adblock Plus, NoScript, Privacy Badger, and Disconnect with 86%, 82%, 80%, 71%, and 69% respectively. In spite of this, NoScript achieves the highest specificity rate of 87% since it is the highest blocker of external third-party services. Followed by Ghostery, uBlock, Adblock Plus, Privacy Badger, and Disconnect with 84%, 82%, 73%, 69%, and 68% respectively. Furthermore, we observed that Ghostery achieved the lowest average error rate (AER) of 0.145, which is calculated as the average of false positive and false negative rates. However, Disconnect achieved the highest average error rate of 0.315 due to its poorest sensitivity and specificity. The average error rate (AER) reports in (Figure 6). The next focus is how fast the browser can render the pages. The page load time or PLT using Chrome DevTools [25], as shown in (Figure 7). Chrome DevTools is a collection of web developer tools integrated directly into the Google Chrome browser. It helps edit pages directly from within the browser and diagnose problems easily. Also, it includes prototyping CSS, debugging CSS and JavaScript, and analyzing load performance. A general conclusion of the study is that privacy protection tools improve the loading time of web pages by blocking incoming requests from third-party services. Comparing initial results (PPTs Off) with each tool, we observe that PPTs decrease the time it takes to render the page by filtering many third parties to contact. Ghostery improves the average load time by 36.2% over the standard browser. Privacy Badger, AdBlock Plus, Disconnect, and uBlock increase the loading speed of the pages by 28.4%, 23.5%, 23.3%, and 22.6% respectively. Furthermore, NoScript also reduces load time with a minor improvement of 7.1%. Further analysis is that we investigated the presence of obfuscation in JavaScript programs. The purpose is to verify the use of obfuscation in web tracking, and how it affects privacy protection tools' classifications.