Two bits of information are pretty easy to get here; the rest I'm going to skip for the time being as it's gonna take more time than I have to retrieve.
Helpful flags
This is pretty self-explanatory: if a flag was marked helpful, it counts; if it wasn't, it doesn't. Spam flags can be marked helpful in the following scenarios:
- A moderator explicitly marks the flag helpful
- The post accumulates enough spam flags to delete the post as spam (w/ locking, penalties, etc.)
- The post is deleted for some other reason (author vote, privileged user vote, LQ review, moderator vote)
Unlike most other flags, spam flags can be retroactively disputed if a moderator decides it wasn't warranted; this can affect the outcome as well.
Here are some numbers for helpful spam flags, network-wide, for the past 365 days:
Site SpamFlags HelpfulSpamFlags PctSpamFlagsHelpful
------------------------------------ --------- ---------------- -------------------
Stack Overflow 36303 30448 83.87 %
Super User 18245 18070 99.04 %
Server Fault 1264 1232 97.47 %
Stack Apps 296 294 99.32 %
Seasoned Advice 325 314 96.62 %
Home Improvement 800 770 96.25 %
Game Development 271 262 96.68 %
Arqade 1995 1948 97.64 %
GIS 199 189 94.97 %
Mathematics 919 821 89.34 %
Photography 317 298 94.01 %
Cross Validated 173 166 95.95 %
Web Applications 2340 2294 98.03 %
Webmasters 686 674 98.25 %
Ask Different 21840 21789 99.77 %
Theoretical Computer Science 18 15 83.33 %
English Language & Usage 901 878 97.45 %
Money 2243 2211 98.57 %
RPG 459 447 97.39 %
TeX - LaTeX 376 369 98.14 %
Ask Ubuntu 46473 46317 99.66 %
Unix & Linux 524 503 95.99 %
WordPress Development 863 828 95.94 %
Bicycles 297 273 91.92 %
Software Engineering 391 380 97.19 %
Android Enthusiasts 1837 1766 96.14 %
Board & Card Games 148 140 94.59 %
Physics 1079 1035 95.92 %
Homebrewing 27 24 88.89 %
Information Security 2588 2570 99.3 %
Writing 256 247 96.48 %
Electrical Engineering 787 765 97.2 %
Graphic Design 23860 23816 99.82 %
DBA 232 222 95.69 %
Science Fiction & Fantasy 690 668 96.81 %
Area 51 Discussions 22 21 95.45 %
Code Review 271 262 96.68 %
Code Golf 543 527 97.05 %
Quantitative Finance 84 71 84.52 %
Project Management 107 107 100 %
Skeptics 343 339 98.83 %
Drupal Answers 15880 15860 99.87 %
Physical Fitness 347 328 94.52 %
Motor Vehicles 401 393 98 %
Parenting 394 389 98.73 %
SharePoint 421 407 96.67 %
Music 302 296 98.01 %
Software Quality Assurance & Testing 246 240 97.56 %
Mi Yodeya 98 90 91.84 %
Astronomy 7330 7325 99.93 %
German Language 149 138 92.62 %
Japanese Language 75 75 100 %
Gardening & Landscaping 95 91 95.79 %
Philosophy 29 28 96.55 %
Personal Productivity 183 180 98.36 %
Travel 2136 2105 98.55 %
Cryptography 131 127 96.95 %
Literature 26 25 96.15 %
Signal Processing 165 164 99.39 %
French Language 64 64 100 %
Christianity 51 49 96.08 %
Bitcoin 1816 1774 97.69 %
Linguistics 22 21 95.45 %
Biblical Hermeneutics 42 39 92.86 %
Economics 34 34 100 %
History 160 158 98.75 %
Bricks 41 41 100 %
Spanish Language 42 41 97.62 %
Computational Science 40 39 97.5 %
Movies & TV 433 417 96.3 %
Chinese Language 144 112 77.78 %
Biology 450 433 96.22 %
Poker 176 158 89.77 %
Mathematica 57 54 94.74 %
Psychology & Neuroscience 71 71 100 %
The Great Outdoors 164 160 97.56 %
Martial Arts 35 34 97.14 %
Sports 108 106 98.15 %
Academia 1374 1345 97.89 %
Computer Science 85 80 94.12 %
The Workplace 4002 3977 99.38 %
Windows Phone 50 46 92 %
Chemistry 272 250 91.91 %
Chess 53 49 92.45 %
Raspberry Pi 128 121 94.53 %
Russian Language 13 13 100 %
Islam 318 305 95.91 %
Salesforce 349 342 97.99 %
Ask Patents 320 318 99.38 %
UX 489 479 97.96 %
Genealogy & Family History 41 41 100 %
Robotics 28 27 96.43 %
ExpressionEngine® Answers 75 73 97.33 %
Politics 106 106 100 %
Video Production 122 115 94.26 %
Anime & Manga 239 236 98.74 %
Magento 764 686 89.79 %
English Language Learners 570 560 98.25 %
Sustainable Living 35 33 94.29 %
Tridion 1 1 100 %
Reverse Engineering 47 46 97.87 %
Arduino 983 975 99.19 %
Network Engineering 65 62 95.38 %
Open Data 54 49 90.74 %
Freelancing 89 77 86.52 %
Blender 91 81 89.01 %
MathOverflow 1635 1628 99.57 %
Space Exploration 54 50 92.59 %
Sound Design 71 68 95.77 %
Tor 109 96 88.07 %
Pets 172 163 94.77 %
Amateur Radio 32 32 100 %
Italian Language 5 5 100 %
Stack Overflow em Português 399 359 89.97 %
Aviation 510 504 98.82 %
Ebooks 137 137 100 %
Beer, Wine & Spirits 60 58 96.67 %
Software Recommendations 321 293 91.28 %
CS50 2 2 100 %
Expatriates 231 230 99.57 %
Mathematics Educators 12 11 91.67 %
Earth Science 43 40 93.02 %
Joomla 191 186 97.38 %
Data Science 74 73 98.65 %
Puzzling 325 316 97.23 %
Craft CMS 56 54 96.43 %
Buddhism 52 50 96.15 %
Hinduism 128 121 94.53 %
Community Building 165 164 99.39 %
Startups 250 232 92.8 %
Worldbuilding 650 626 96.31 %
スタック・オーバーフロー 50 48 96 %
Emacs 3 2 66.67 %
History of Science and Mathematics 14 13 92.86 %
Lifehacks 180 168 93.33 %
Engineering 55 52 94.55 %
Coffee 50 39 78 %
Vi and Vim 3 1 33.33 %
Music Fans 57 55 96.49 %
Woodworking 113 110 97.35 %
CiviCRM 150 136 90.67 %
Health 892 877 98.32 %
Stack Overflow на русском 1135 1030 90.75 %
Русский язык 57 51 89.47 %
Mythology & Folklore 37 36 97.3 %
Law 161 160 99.38 %
Open Source 33 29 87.88 %
elementary OS 14 14 100 %
Portuguese Language 5 5 100 %
Computer Graphics 8 8 100 %
Hardware Recommendations 25 17 68 %
Stack Overflow en español 327 258 78.9 %
3D Printing 579 498 86.01 %
Ethereum 270 265 98.15 %
Latin Language 12 11 91.67 %
Language Learning 7 7 100 %
Retrocomputing 20 20 100 %
Arts & Crafts 72 72 100 %
Korean Language 2 2 100 %
Monero 65 64 98.46 %
Artificial Intelligence 86 83 96.51 %
Esperanto Language 8 0 0 %
Sitecore 16 14 87.5 %
Internet of Things 49 48 97.96 %
Vegetarianism 58 57 98.28 %
Ukrainian Language 1 1 100 %
DevOps 4 3 75 %
Bioinformatics 4 3 75 %
Computer Science Educators 21 20 95.24 %
Interpersonal Skills 698 689 98.71 %
Augur 5 5 100 %
Effective flags
Now, not every flag marked helpful was actually effective... As you might well guess from the description above; obviously a spam flag that's cleared by Low Quality review didn't end up doing much! You could argue that a spam flag which prompts a moderator - or even a post author - to delete a post is still effective in some sense... And you can go right ahead and argue that, but for the purpose of the next table I'm going to consider a spam flag to be helpful only if it resulted in the flagged post being deleted as spam - that is, either enough other people flagged it as spam or a moderator flagged it as spam - and then it stayed deleted afterwards.
Again, past 365 days:
Site SpamFlags EffectiveSpamFlags PctSpamFlagsEffective
------------------------------------ --------- ------------------ ---------------------
Stack Overflow 36304 22791 62.78 %
Super User 18243 17541 96.15 %
Server Fault 1264 1082 85.6 %
Stack Apps 296 282 95.27 %
Seasoned Advice 325 249 76.62 %
Home Improvement 800 724 90.5 %
Game Development 271 207 76.38 %
Arqade 1995 1703 85.36 %
GIS 199 103 51.76 %
Mathematics 919 557 60.61 %
Photography 317 185 58.36 %
Cross Validated 173 101 58.38 %
Web Applications 2340 2196 93.85 %
Webmasters 686 299 43.59 %
Ask Different 21840 21339 97.71 %
Theoretical Computer Science 18 7 38.89 %
English Language & Usage 901 821 91.12 %
Money 2243 1584 70.62 %
RPG 459 413 89.98 %
TeX - LaTeX 376 243 64.63 %
Ask Ubuntu 46473 45851 98.66 %
Unix & Linux 524 368 70.23 %
WordPress Development 863 576 66.74 %
Bicycles 297 170 57.24 %
Software Engineering 391 286 73.15 %
Android Enthusiasts 1837 1652 89.93 %
Board & Card Games 148 108 72.97 %
Physics 1079 906 83.97 %
Homebrewing 27 20 74.07 %
Information Security 2588 2329 89.99 %
Writing 256 216 84.38 %
Electrical Engineering 787 479 60.86 %
Graphic Design 23860 23613 98.96 %
DBA 232 182 78.45 %
Science Fiction & Fantasy 690 583 84.49 %
Area 51 Discussions 22 21 95.45 %
Code Review 271 192 70.85 %
Code Golf 543 498 91.71 %
Quantitative Finance 84 28 33.33 %
Project Management 107 84 78.5 %
Skeptics 343 276 80.47 %
Drupal Answers 15880 15380 96.85 %
Physical Fitness 347 212 61.1 %
Motor Vehicles 401 340 84.79 %
Parenting 394 302 76.65 %
SharePoint 421 244 57.96 %
Music 302 277 91.72 %
Software Quality Assurance & Testing 246 132 53.66 %
Mi Yodeya 98 74 75.51 %
Astronomy 7330 7258 99.02 %
German Language 149 132 88.59 %
Japanese Language 75 63 84 %
Gardening & Landscaping 95 90 94.74 %
Philosophy 29 14 48.28 %
Personal Productivity 183 167 91.26 %
Travel 2136 1670 78.18 %
Cryptography 131 103 78.63 %
Literature 26 23 88.46 %
Signal Processing 165 153 92.73 %
French Language 64 52 81.25 %
Christianity 51 39 76.47 %
Bitcoin 1816 1080 59.47 %
Linguistics 22 12 54.55 %
Biblical Hermeneutics 42 21 50 %
Economics 34 18 52.94 %
History 160 95 59.38 %
Bricks 41 26 63.41 %
Spanish Language 42 22 52.38 %
Computational Science 40 25 62.5 %
Movies & TV 433 379 87.53 %
Chinese Language 144 78 54.17 %
Biology 450 383 85.11 %
Poker 176 127 72.16 %
Mathematica 57 31 54.39 %
Psychology & Neuroscience 71 49 69.01 %
The Great Outdoors 164 129 78.66 %
Martial Arts 35 16 45.71 %
Sports 108 75 69.44 %
Academia 1374 1164 84.72 %
Computer Science 85 69 81.18 %
The Workplace 4002 3947 98.63 %
Windows Phone 50 35 70 %
Chemistry 272 230 84.56 %
Chess 53 38 71.7 %
Raspberry Pi 128 73 57.03 %
Russian Language 13 6 46.15 %
Islam 318 245 77.04 %
Salesforce 349 251 71.92 %
Ask Patents 320 315 98.44 %
UX 489 431 88.14 %
Genealogy & Family History 41 36 87.8 %
Robotics 28 10 35.71 %
ExpressionEngine® Answers 75 60 80 %
Politics 106 79 74.53 %
Video Production 122 104 85.25 %
Anime & Manga 239 160 66.95 %
Magento 764 223 29.19 %
English Language Learners 570 462 81.05 %
Sustainable Living 35 20 57.14 %
Tridion 1 0 0 %
Reverse Engineering 47 25 53.19 %
Arduino 983 885 90.03 %
Network Engineering 65 42 64.62 %
Open Data 54 17 31.48 %
Freelancing 89 63 70.79 %
Blender 91 51 56.04 %
MathOverflow 1635 1355 82.87 %
Space Exploration 54 21 38.89 %
Sound Design 71 56 78.87 %
Tor 109 93 85.32 %
Pets 172 135 78.49 %
Amateur Radio 32 29 90.63 %
Italian Language 5 0 0 %
Stack Overflow em Português 399 157 39.35 %
Aviation 510 422 82.75 %
Ebooks 137 117 85.4 %
Beer, Wine & Spirits 60 51 85 %
Software Recommendations 321 212 66.04 %
CS50 2 0 0 %
Expatriates 231 190 82.25 %
Mathematics Educators 12 8 66.67 %
Earth Science 43 25 58.14 %
Joomla 191 161 84.29 %
Data Science 74 51 68.92 %
Puzzling 325 241 74.15 %
Craft CMS 56 41 73.21 %
Buddhism 52 39 75 %
Hinduism 128 67 52.34 %
Community Building 165 145 87.88 %
Startups 250 185 74 %
Worldbuilding 650 575 88.46 %
スタック・オーバーフロー 50 43 86 %
Emacs 3 2 66.67 %
History of Science and Mathematics 14 6 42.86 %
Lifehacks 180 105 58.33 %
Engineering 55 28 50.91 %
Coffee 50 36 72 %
Vi and Vim 3 0 0 %
Music Fans 57 35 61.4 %
Woodworking 113 93 82.3 %
CiviCRM 150 117 78 %
Health 892 558 62.56 %
Stack Overflow на русском 1135 620 54.63 %
Русский язык 57 34 59.65 %
Mythology & Folklore 37 33 89.19 %
Law 161 101 62.73 %
Open Source 33 23 69.7 %
elementary OS 14 12 85.71 %
Portuguese Language 5 3 60 %
Computer Graphics 8 5 62.5 %
Hardware Recommendations 25 13 52 %
Stack Overflow en español 327 49 14.98 %
3D Printing 579 490 84.63 %
Ethereum 270 115 42.59 %
Latin Language 12 8 66.67 %
Language Learning 7 6 85.71 %
Retrocomputing 20 15 75 %
Arts & Crafts 72 62 86.11 %
Korean Language 2 1 50 %
Monero 65 39 60 %
Artificial Intelligence 86 81 94.19 %
Esperanto Language 8 0 0 %
Sitecore 16 0 0 %
Internet of Things 49 23 46.94 %
Vegetarianism 58 45 77.59 %
Ukrainian Language 1 0 0 %
DevOps 4 1 25 %
Bioinformatics 4 2 50 %
Computer Science Educators 21 13 61.9 %
Interpersonal Skills 698 638 91.4 %
Augur 5 3 60 %