26

Someone argued with me that people in the SE network don't try to delete stuff actively (voting to delete) and leave that work to the Community user. I'm not convinced. So… I would like some stats about how much stuff gets deleted by 10kers network-wide by sites.

Extra points if the data includes:

  • the amount of closed stuff vs deleted stuff.
  • how long people wait until it gets deleted (or the question gets deleted) after being closed.
  • 1
    I thought that Community only deleted spam and abandoned questions, though. Why wouldn't a 10ker (let alone Moderator) take a more proactive approach to deleting things? Community only does it in those specific cases. – Makoto Feb 16 '14 at 3:18
  • 1
    Community also deletes questions with one or more downvotes, without answers, after 30 days IIRC. There's plenty of arguments against letting zealous users insta-deleting everything they don't like so this is something very much worth knowing about. – Pekka supports GoFundMonica Feb 16 '14 at 3:27
  • @Makoto community deletes 0 voted stuff after a while, but 10kers can cast delete votes on questions after 24 hours closed. – Braiam Feb 16 '14 at 3:28
  • So I'm not opposed to knowing the numbers; I'm merely stating that Community doesn't delete all that much. Also, it seems that the three of us are in agreement in what Community deletes - abandoned questions. – Makoto Feb 16 '14 at 3:30
  • Run an SEDE query and find out. – Robert Harvey Feb 16 '14 at 3:30
  • @Makoto oh, misunderstood your comment. – Braiam Feb 16 '14 at 3:30
  • 3
    @Robert how would one build a SEDE query to find deleted questions? I was under the impression that wasn't possible, let alone knowing who deleted them – Pekka supports GoFundMonica Feb 16 '14 at 3:31
  • @RobertHarvey SEDE doesn't keep track of deleted stuff, at least that's what I've seen. – Braiam Feb 16 '14 at 3:31
  • @Pëkka: Apparently it is. – Robert Harvey Feb 16 '14 at 3:31
  • 3
    @Robert those seem like attempts to see deleted questions for a specific user, but from a quick skim of the results, I can't find any where it was successful – Pekka supports GoFundMonica Feb 16 '14 at 3:33
  • @RobertHarvey the only that do something (but the opposite) of what I want is Closed but not deleted query – Braiam Feb 16 '14 at 3:34
  • [sigh] If you take my word for it, can I give you an educated guess without proof? – Robert Harvey Feb 16 '14 at 3:36
  • 1
    Oh, totally ------- – Pekka supports GoFundMonica Feb 16 '14 at 3:38
  • 1
    related: Turbocharging the Roomba: solutions for premature deletion "Automatic deletion of closed, abandoned questions for questions meeting the following criteria: * Closed more than 9 days ago * Not closed as a duplicate * Score <= 0 * Not locked * No answers with a score > 0 * No accepted answer * No pending reopen votes * No edits in the past 9 days..." – gnat Feb 17 '14 at 17:32
  • @Makoto according to Shog, you are wrong... or right... I'm not sure – Braiam Aug 5 '14 at 22:09
57

I'm glad you asked this... There are a lot of misconceptions surrounding how much stuff gets deleted, and who is responsible - so I'm going to provide a bit more information than what you asked for, in hopes of clearing this up.

Questions deleted during the past 365 days on Stack Overflow

  • 659,974 questions were deleted in total
  • 387,197 were deleted by the Community user (abandoned and user deletion)
  • 237,712 were deleted by their authors
  •   20,081 were deleted by moderators
  •   16,056 were deleted by votes from users with 10K+ reputation (overlaps with above)
  •     1,069 were deleted by the community via spam or offensive flags

Answers deleted during the past 365 days on Stack Overflow

  • 797,477 answers were deleted in total
  • 360,297 were deleted by their authors
  • 245,801 were deleted because the questions they answered were deleted
  • 166,060 were deleted by moderators
  •   17,946 were deleted by the community via the Low Quality review queue
  •     4,460 were deleted by votes from users with 20K+ reputation (overlaps with above)
  •     2,650 were deleted by the Community user (user deletion)
  •     1,750 were deleted by the community via spam or offensive flags

Questions deleted during the past 365 days network-wide

Not doing answers since it's a bit tedious.

Site Name                                 AllDeleted AuthorDeleted SpamOffensiveDeleted Deleted10K DeletedCommunity DeletedModerators  
Stack Overflow                            660028     237756        1070                 16062      387197           20083            
Super User                                 22226       4071         299                    19       15955            1854            
Server Fault                               17938       3138          46                   156       14004             632            
Stack Apps                                   167         27          10                     0          68              54            
Cooking                                      366         53          11                     0         270              28            
Home Improvement                             567         81          32                     0         428              24            
Game Developers                             3671        950          67                     0        2504             157            
Gaming                                      2916        740         112                   276        1546             252            
GIS                                         2092        700          21                     0        1293              81            
Mathematics                                21419      10663         102                   218       10028             378            
Photography                                  495        122           3                     1         321              53            
Statistical Analysis                        3699       1221           1                     1        2379             107            
Web Apps                                    3504        327         227                     0        2340             484            
Webmasters                                  3013        383          25                     0        2458             120            
Apple                                       3187        512         166                     0        2177             228            
Theoretical Computer Science                1258        413           9                     1         812               7            
English Language and Usage                  4178        617          46                   120        2844             514            
Personal Finance and Money                   666        112           7                    81         114             103            
Role-playing Games                           302         79           6                     1          94             121            
TeX - LaTeX                                 3154       1005         197                    14        1879              55            
Ubuntu                                     24130       3360         405                    68       19465             568            
Unix and Linux                              2432        837          45                     1        1469              55            
WordPress                                   7819       1879          50                     0        5603             300            
Bicycles                                     168         36          10                     0         102              18            
Programmers                                 9857       1748          46                   851        4955            2559            
Android Enthusiasts                         3282        578          67                    87        1058            1530            
Board and Card Games                          96         24           1                     0          64               7            
Physics                                     4676       1250          24                     0        3196             182            
Homebrew                                      25          2           0                     0          10              13            
IT Security                                 2049        389         111                     8        1411             127            
Writers                                      233         43          10                     0         151              28            
Electronics and Robotics                    3140        740          49                     1        2230             104            
Graphic Design                               747        172           2                     0         442             136            
Database Administrators                     1970        502          13                     4        1384              63            
Science Fiction                              687        138           7                     8         465              72            
Code Review                                 2317        723           4                     3         949             598            
Code Golf                                    298        144           2                     3         113              19            
Quantitative Finance                         546        133           0                     0         387              28            
Project Management                           200        26            3                     0         132              39            
Skeptics                                     729        178          14                     0         345             190            
Drupal Answers                              6185       1118          83                     0        4363             176            
Fitness and Nutrition                        393         87           4                     0         252              46            
Motor Vehicle Maintenance and Repair         120         22           2                     0          82              14            
Parenting                                     95         21           2                     0          50              22            
SharePoint                                  2684        600          11                     0        2007              46            
Musical Practice and Performance             274         65           3                     0         179              27            
Software Quality Assurance and Testi         143         30           0                     0          97              16            
Jewish Life and Learning                     360         91          18                     0         211              43            
Astronomy                                     84         25           2                     0          38              19            
German Language and Usage                     79         23           1                     1          42               8            
Japanese Language and Usage                  156         49           2                     0          83              27            
Gardening and Landscaping                     62         19           1                     0          39               4            
Philosophy                                   333         96           0                     0         199              40            
Personal Productivity                        143         31           4                     0          95              12            
Travel                                       645        138          14                     0         367             122            
Cryptography                                 597        178           0                     0         408              13            
Signal Processing                            479        244           0                     0         223              13            
French Language and Usage                     83         26           6                     0          48               5            
Christianity                                 806        189          26                    30         348             217            
Bitcoin                                      916        235          39                     0         329             298            
Linguistics                                  135         31           0                     0          86              18            
Biblical Hermeneutics                        212         30           4                     0          76              97            
History                                      357        103           2                     0         186              29            
LEGO®                                         35          8           0                     0          15              12            
Spanish Language and Usage                    50          3           0                     0          34              14            
Computational Science                        294        114           0                     0         169              12            
Movies                                       438        111           1                     0         202             125            
Chinese Language and Usage                    71         17           2                     0          27              27            
Biology                                      461        119          16                     0         265              51            
Poker                                         23          6           1                     0          10               6            
Mathematica                                 2348        690          27                    55         815             768            
Cognitive Sciences                           172         35           1                     0          93              35            
The Great Outdoors                            29          7           3                     0          13               6            
Martial Arts                                  40          6           1                     0          19              14            
Sports                                       139         31           2                     0          94              10            
Academia                                     724        134          11                    18         199             116            
Computer Science                            1336        456           7                     0         701             146            
The Workplace                                789        207           5                    57         245             146            
Windows Phone                                108         26           4                     0          63              18            
Chemistry                                    423         84          32                     0         227              61            
Chess                                         40         16           2                     0          12              10            
Raspberry Pi                                 203         93           1                     0          97              10            
Russian Language and Usage                    63         11           1                     0          19              31            
Islam                                        340         45           7                     0         191             107            
Salesforce                                   488        246          29                     0         175              27            
Patents                                      560         27          21                     0         151             357            
User Experience                             1079        239          31                     0         761              50            
Genealogy and Family History                  24          6           2                     0           7              11            
Robotics                                     117         28           0                     0          76              13            
ExpressionEngine                             299        157           0                     0         120              21            
Politics                                     168         22           1                     0          65              82            
Audio-Video Production                      1850         67           0                     0         216            1569            
Anime and Manga                              181         66           1                     0          95              25            
Magento                                      735        375          35                     0         229              71            
English Language Learners                    459        192           1                     4         218              45            
Sustainable Living                            36          8           2                     0          18               8            
Tridion Stack Exchange                        49         32           0                     0          12               5            
Reverse Engineering Stack Exchange           112         44           0                     0          59              10            
Network Engineering Stack Exchange           655        147           8                     0         441              65            
Open Data Stack Exchange                      31          8           1                     0          18               4            
Blender Stack Exchange                       221         77           0                     0         130              18            
MathOverflow                                8148       1777         214                   663        4488             453            
Space Exploration Stack Exchange             124         61           1                     0          42              20            
Sound Design Stack Exchange                  162         17           3                     0          92              49            
Tor Stack Exchange                            50          9           1                     0          20              19            
Pets Stack Exchange                           53         32           0                     0          12              10            
Amateur Radio Stack Exchange                  47         18           2                     0          11              13            
Italian Language Stack Exchange               10          6           0                     0           2               2            
Stack Overflow em Português                   82         42           1                     0           0              18            
Aviation Stack Exchange                       24         11           3                     0           6               5            
Ebooks Stack Exchange                         28          6           6                     0           5              11            
Total                                     859506     285262        4031                 18812      513429           37989              
  • 14
    Over 2,000,000 posts vanish every year! A silent massacre. A s̶l̶a̶u̶g̶h̶t̶e̶r̶ ̶o̶f̶ ̶i̶n̶n̶o̶c̶e̶n̶t̶.̶.̶.̶ good riddance. – Caleb Feb 17 '14 at 9:40
  • 3
    One thing that catches the eye is how little significance the Low Quality review queue has in the grand scheme of things. Doesn't take much work off the moderators, either. – Monolo Feb 17 '14 at 9:41
  • 2
    @Monolo I don't think that conclusion can be derived from this data. It doesn't say how many posts went into that queue or what else happened to them. Maybe the fact that they went into the queue was what got them flagged and mod deleted. Maybe a lot of things got voted on and edited and deletion wasn't the needed course of action anyway. Just because the final outcome was't a community delete and hence not a big statistic in this breakdown doesn't mean the queue isn't serving a worthwhile function. – Caleb Feb 17 '14 at 9:47
  • 3
    Also, 18K isn't exactly small - it just looks small next to the numbers above it. Considering it's several times the number of answers deleted by 20K users, it's fairly significant. – Shog9 Feb 17 '14 at 9:49
  • Has the current Low Quality review queue allow deleting of answers been going for over a yaer? – Ian Ringrose Feb 17 '14 at 9:51
  • Yes, @Ian. However, VLQ flags have only been feeding into that queue for about 6 months - so the volume hasn't been at all consistent throughout the year. – Shog9 Feb 17 '14 at 9:54
  • 2
    Interesting when you compare to a "is:question created:2013" search for each site. For instance, while the 22% deletion rate at SO seems high, it's nothing compared to a site like Programmers, which sports a 57% rate. – Geobits Feb 17 '14 at 18:04
  • 1
    @Geobits Programmers is still doing cleanup of its skeletons from the NPR days. We also get more than a few people who get question banned on SO and ask on P.SE (which gets closed for off topic). There's also active voting (up and down) on all questions which feeds the roomba scripts (half of the deletes are automatic, and 80% of the remaining deletes are embarrassingly bad that a mod does it). Realize also that the deletes are not just from this years questions (going back to the NPR cleanups). – user213963 Feb 17 '14 at 18:42
  • @MichaelT Oh, I know most of that. These were just the best numbers I could get with my non-staff powers. I wasn't making a judgement call, just pointing it out as interesting. You can see most of the "small" sites have a low rate, such as RPG's 12%. Most likely trying to build up a base of questions, and it probably helps to be more of a "niche" site. The raw numbers themselves don't tell the whole story, obviously. Even from my brief visits to Programmers, it's easy to see that much more gets closed, but it's normally for a good reason, as you said. – Geobits Feb 17 '14 at 18:48
  • 3
    @Geobits one of the bits that would be interesting would be to try to correlate this data with the number of votes per question data. Smaller sites that don't do a lot of active voting seem to have a higher percentage of roomba eaten questions (the abandoned question cleanup). – user213963 Feb 17 '14 at 18:50
  • Why are so many answers deleted by moderators? Is there not a way to remove more of the workload from moderators? – Ian Ringrose Feb 18 '14 at 11:25
  • @IanRingrose its a question of how active and willing the 10ks are to help do that. It also takes a number of 10k votes, diamonds may see the recent votes and say "yep" and do the delete with 1 10k vote logged (rather than the 3+) and have it show up as a moderator delete. – user213963 Feb 18 '14 at 17:45
  • Nice figures. But these deleted questions are not removed completely right? Still 10k users can view them right? – Praveen Feb 23 '14 at 16:24
  • 2
    They're "soft" deleted, @Praveen. See: meta.stackexchange.com/questions/5221/… – Shog9 Feb 23 '14 at 16:25
  • 1
    If you still have the script, how about an update? I'd be interested in how things changed. – Daniel Fischer Jun 14 '15 at 14:05
10

The community actively deletes enough poor quality questions to keep the site reasonably clean.

Questions are only eligible for immediate deletion by the community when they score -3. In my experience, the number of those questions that might be useful to someone else is vanishingly small. They are the usual vague, underspecified, shoddy questions that we've all come to know and love.

The remaining questions may or may not get deleted (after a 24 hour wait), depending on whether or not the community wants to keep them around. Many of them may stay on the site for quite awhile due to lack of interest, which is why we have some automated deletion algorithms now.

Of the rest (zero or positive score), I'd say that relatively few that are useful to others actually get deleted. The ones that are... well, they're just not useful to anyone else. It's extremely rare that a question gets deleted if it might be useful to someone, even if it's closed.

The ones that are useful but do get deleted are contentious in some way; they've managed to skirt the community rules for question quality, gather a lot of upvotes, and get closed and reopened. Community deletions are a pretty effective (but difficult) way of disposing of them. I say difficult, because it takes many delete votes to delete these kinds of questions.

You can get a very good feel for the kind and quantity of questions that get deleted (and undeleted) on a regular basis by looking here (10k only).

  • 1
    Yeah, but no hard numbers :( – Braiam Feb 16 '14 at 3:46
  • Nope. No hard numbers. – Robert Harvey Feb 16 '14 at 3:47
  • @Braiam Robert's not in the position to provide them; probably only devs could. Either way, if a mod is satisfied that what's being deleted is mostly garbage, then I am, too... I sometimes have the impression that newbs are getting awfully quickly downvoted and their questions deleted even before they manage to check back to the site, but then, it's how the system works – Pekka supports GoFundMonica Feb 16 '14 at 3:49
  • @Pëkka but then we are missing the point of my question. Everything told here I know about it already (I'm 10ker in AU), what I do not know is how active are people deleting stuff which is why I want the stats. – Braiam Feb 16 '14 at 3:51
  • Then maybe you'd better clarify your question. I've already stated that the commmunity is quite actively deleting crappy questions, but generally leaves the decent stuff alone. Numbers will only tell you that the community actively deletes questions. They do. – Robert Harvey Feb 16 '14 at 3:53
  • @RobertHarvey I want to know how many of those question that gather +1 votes or at least 1 answer with +1 gets deleted by 10kers or crappy stuff that people doesn't wait for Community to be deleted. – Braiam Feb 16 '14 at 3:54
  • Did you look at the page I linked? stackoverflow.com/tools?tab=delete&daterange=today – Robert Harvey Feb 16 '14 at 3:55
  • 3
    The only way I can see that one is if I have 10k on SO, but I don't. I want the network wide (aka every site in SE) for comparisons between all sites. I can see up to 3 questions deleted on Ask Ubuntu which I have 10k rep. – Braiam Feb 16 '14 at 3:59
  • 1
    I'll ping a community manager and see if they have any interest in digging up this data for you. – Robert Harvey Feb 16 '14 at 4:00

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