## 4 Content Analysis in Twitter
* NDCRS: The new Dale-Chall readability formula outputs values of 0-20 (grade levels). It compares a text against several words considered familiar to fourth-graders. The more unfamiliar words that are used, the higher the reading level. A value \(\leq\)4.9 means grade \(\leq\)4, whereas a value \(\geq\)10 means grades \(\geq\)16 (college graduate). * ARI: The automated readability index outputs values of 5-22 (age related to grade levels). This index relies on a factor of characters per word. A value of 15-16 means a high school student level (10-grade level). * FKI: The Flesch-Kincaid index (grade levels) outputs values of 0-18. The index assesses the approximate reading grade level of a text. Level 8 means that the reader needs a grade level \(\geq\)8 in order to understand (13-14 years old). \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Feature** & **Range** & **Social Out.** & **COVID-19** & **2021 Elect.** & **Constitution** & **Other** \\ \hline Length in chars * & \(\{0,\infty\}\) & \(\downarrow\) 2561 & 4179 & 4907 & 4815 & 4774 \\ Length in words * & \(\{0,\infty\}\) & \(\downarrow\) 422 & 690 & 807 & 783 & 788 \\ Valence & \([0,10]\) & 5.68 & 5.87 & 5.94 & 6.03 & 6.09 \\ Arousal & \([0,10]\) & 5.33 & 5.25 & 5.26 & 5.25 & 5.29 \\ Dominance & \([0,10]\) & 5.05 & 5.12 & 5.15 & 5.16 & 5.17 \\ Entropy & \(-\infty,0[\) & \(-4.24\) & \(-4.25\) & \(-4.29\) & \(-4.25\) & \(-4.28\) \\ Emoticons & \([0,100]\) & 0 & 0.02 & 0 & 0 & 0 \\ Verbs & \([0,100]\) & 8.9 & 8.9 & 8.6 & 8.7 & 8.3 \\ Determiners & \([0,100]\) & 14.2 & 14.3 & 13.2 & 15.0 & 14.1 \\ Nouns & \([0,100]\) & 21.2 & 20.8 & 19.8 & 20.6 & 20.6 \\ Proper nouns * & \([0,100]\) & 12.8 & 11.5 & \(\uparrow\) **15.0** & 12.0 & 13.3 \\ Ad-positions & \([0,100]\) & 18.6 & 17.7 & 18.4 & 17.6 & 18.6 \\ Persons * & \([0,100]\) & 1.5 & 1.1 & \(\uparrow\) 2.3 & 1.4 & 1.4 \\ Locations & \([0,100]\) & 1.5 & 1.8 & 1.4 & 1.2 & 1.7 \\ Organizations & \([0,100]\) & 1.5 & 1.1 & 1.5 & 1.7 & 1.5 \\ Miscellaneous & \([0,100]\) & 2.5 & 2.4 & 2.5 & 2.6 & 2.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Linguistic features for units of content verified in Twitter per topic dimension. Features marked with * and values in red indicate significant differences. Upward and downward arrows indicate whether the value is higher or lower than that of the other categories. We used one-way ANOVA to compare the means of the five groups at a level of significance = 0.05. * DCRS: The Dale-Chall readability formula outputs values of 0-20 (grade levels). It compares a text against 3000 familiar words for at least 80% of fifth-graders. The more unfamiliar words that are used, the higher the reading level. * CLI: The Coleman--Liau index outputs values of 0-20. The index assesses the approximate reading grade level of a text. * LWRI: The Linear Write reading ease index scores monosyllabic words and strong verbs. It outputs values of 0-100, where higher indicates easier. * FRE: The Flesch reading ease index gives a score between 1-100, with 100 being the highest readability score. Scoring between 70-80 is equivalent to school grade level 8. Higher indicates easier. * IFSZ: The index of Flesch-Szigriszt standardized for Spanish text [48] outputs values of 1-100. The readability of the text is interpreted as follows: very difficult (\(<\)40), somewhat difficult (40-55), normal (55-65), easy (65-80), and very easy (\(>\)80). * FHRI: The Fernandez-Huerta readability index for Spanish texts [49] outputs values of 1-100. The readability of the text is interpreted as follows: beyond college (\(<\)30), college (30-50), 12 th grade (50-60), 8 th grade (60-70), 6 th grade (70-80), 5 th grade (80-90), and 4 th grade (90-100). We show the results of this analysis per veracity category in Table 7.  
The first six metrics in Table 7 correspond to grade levels. These metrics indicate that the complexity of the texts is in the range of basic-to-medium complexity. We found significant differences between content types when calculating GFOG, ARI, FKI, and CLI.