Table 2.
Description of included studies, sample size, and coding method.
| Authors, year, country | Social media platform | Sample size | Coding method |
| Burke-Garcia et al, 2017, United States [39] | 1000 tweets | Hand coding | |
| Lazard et al, 2017, United States [40] | 4629 tweets | Machine learning and hand coding | |
| Allem et al, 2017, United States [31] | 2192 tweets | Hand coding | |
| Ayers et al, 2017, United States [17] | 11,600 tweets | Hand coding | |
| Dai et al, 2017, United States [45] | 757,167 tweets | Hand coding and machine learning | |
| Clark et al, 2016, United States [16] | 850,000 tweets | Hand coding, machine learning, and hedonometrics | |
| van der Tempel et al, 2016, Canada [42] | 600 tweets | Hand coding | |
| Han et al, 2016, United States [35] | 1,021,561 tweets | Hand coding and machine learning | |
| Jo et al, 2016, United States [36] | 2847 tweets | Hand coding | |
| Kavuluru et al, 2016, United States [43] | 224,000 tweets | Hand coding and machine learning | |
| Sowles et al, 2016, United States [37] | 1156 tweets | Hand coding | |
| Unger et al, 2016, United States [38] | 1519 tweets | Hand coding | |
| Lazard et al, 2016, United States [44] | 126,127 tweets | Machine learning | |
| Cole-Lewis et al, 2015, United States [41] | 10,128 tweets | Hand coding | |
| Kim et al, 2015, United States [34] | 1,669,123 tweets | Hand coding and machine learning | |
| Harris et al, 2014, United States [32] | 683 tweets | Hand coding | |
| Huang et al, 2014, United States [33] | 73,672 tweets | Handing coding and machine learning | |
| Prochaska et al, 2012, United States [46] | 153 accounts | Hand coding | |
| Sears et al, 2017, United States [47] | YouTube | 46 videos | Hand coding |
| Basch et al, 2016, United States [48] | YouTube | 99 videos | Hand coding |
| Merianos et al, 2016, United States [49] | YouTube | 55 videos | Hand coding |
| Huang et al, 2016, United States [50] | YouTube | 28,089 videos tags, titles, or descriptions | Hand coding |
| Lee et al, 2017, United States [51] | Instagram and Pinterest | 1800 images | Hand coding |
| Chu et al, 2016, United States [52] | 2208 posts | Hand coding | |
| Laestadius et al, 2016, United States [53] | 85 posts | Hand coding |