Wikipedia talk:Modelling Wikipedia's growth

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Contents 1 Error analysis 2 Followup 3 Exponential growth 4 Estimates beaten 5 Software notice 6 Suggestion to improve results 7 Update needed 8 Simpler model 9 Are the artifacts still bad? 10 My new model 11 Unclear what variable represents 12 What happened arround Oct. 2002? 13 Added plot of log(pages) vs. time to demonstrate exponential growth 14 Automatic modelling 15 Google Trends 16 The December 2003 model predictions vs. actual data 17 Logistic growth model

[edit] Error analysis

How about some error analysis for the estimates, and the model predictions? --Anon.

[edit] Followup

This should be revisited in 3 to 6 months (ie in Sept 2003, or Dec 2003), to see whether the new data fits the predicted trend line. --Anon.

[edit] Exponential growth

I have no doubt that there is an exponential growth. Bibliometric shows that the number of publications doubles every 20 years - even wars did not stop this trends (in this case there is smaller groth but faster afterwards).

You should have a look at parts of the curve without artifacts so you will get values of the λ in the exponential growth function N = N₀·e^λt. N may be the number of articles, links, users, traffic... (different λ and N₀ of course). Since little change of λ results in big changes in the future, better do not try to predict more than 3 years. Especially when there is a modification in article count every 18 month ;-)

See also the plot at de:Wikipedia:Statistik. There is an OpenOffice Calc or Excel chart, ask de:Benutzer:TomK32 --Nichtich 00:52 14 Jul 2003 (UTC)

[edit] Estimates beaten

The growth predictions on the graph on this page have already been beaten by quite a margin (it predicts that about 110,000 articles will have been reached by january 2004, which was already reached months ago). Chances are that by Jan 2004 the article count will be closer to 200,000. Isn't it time this was updated and revised. --G-Man 21:56, 27 Sep 2003 (UTC)

[edit] Software notice

While I didn't come to any conclusions, the software I created for User:Jrincayc/Wikipedia Growth Paper#Conclusions is at least more powerful and can do things like filter out robot edits. --Jrincayc 13:27, 21 Apr 2004 (UTC)

[edit] Suggestion to improve results

Wouldn't the results be much more stable if you look at number of pages per time? Growth is the derivation of the actual value and much more fragile. Easierst way to see if a function is exponetial is looking at logarithm of it. If this is linear growing you have an exponential growth.

[edit] Update needed

We need to update the graphs, as well as remove the obsolete ones. --Christopher 12:19, Mar 1, 2005 (UTC)

[edit] Simpler model

The equation Y = .49X² + 13.59X + 175.6, which is simpler than the current one, fits surprisingly well with the data. --Bart133 (t) 16:31, 17 Mar 2005 (UTC)

[edit] Are the artifacts still bad?

The line about artifacts in the data making it impossible to see wether the trend is exponential, linear or whatever (which probably was appropriate just after the addition of all the towns), isn't really appropriate any more, is it? --62.79.161.178 15:37, 24 Jun 2005 (UTC)

[edit] My new model

Should I write a section on my own growth model? Image:Wikigrowthjul05.jpg --Ctrl build^talk 23:36, 13 July 2005 (UTC)

Absolutely. I'd be interested to see how your model works. As an aside how close were your predictions for this month (August 2005)? --Lisiate 01:59, 19 August 2005 (UTC)

[edit] Unclear what variable represents

on the formula used for the Dec 2003 model, what is d? --207.200.116.195 05:57, 8 August 2005 (UTC)

[edit] What happened arround Oct. 2002?

What happened on october 2002 to cause such a big bump? --Bawolff 00:13, 2 October 2005 (UTC)

In October 2002 Ram-Man used the bot Rambot to add a very large number of articles about U.S. towns; these articles were automatically generated from U.S. census data. As you can see, at the time it made a big difference to the total number of English Wikipedia articles. --CheekyMonkey 11:44, 2 October 2005 (UTC)

[edit] Added plot of log(pages) vs. time to demonstrate exponential growth

I added a plot of the log(English language pages) vs. time and it look VERY linear demonstrating exponential growth.

To me this shows that the more pages are out there, the more people read them, the more readers are "converted" to editors, and these people then create new pages. I would like to see if people are starting to do statistical analysis of pages, page types etc. to create knowledge bases like Cyc.

I put it into a spreadsheet and was going to try to get the TREND() function to work but no luck so far. Let me know if someone else is an Excel expert.

--Dan 21:48, 11 April 2006 (UTC)

[edit] Automatic modelling

I have made a gnuplot/ruby script which, given a file containing article creation dates, plots the size of wikipedia and fits a few functions to it (exponential, logistic, power series), and generates png-images of this. Results are here and here. I can't generate the text files used as a basis myself, but it should be possible to use something like this to automatically keep this page up to date. The scripts themselves are linked from my user page. Amaurea 14:53, 23 April 2006 (UTC)

[edit] Google Trends

Look at the folloking graph:

http://www.google.com/trends?q=%22Wikipedia%22&ctab=0&date=all&geo=all

Far too good information not to use... But where and how?

It's even more interesting when you compare it to some competitors:

http://www.google.com/trends?q=wikipedia%2C+encyclopedia%2C+encarta%2C+britannica&ctab=0&geo=all&date=all - mennonot 22:00, 19 May 2006 (UTC)

See Wikipedia talk:Awareness statistics#Google Trends. --Zoz (t) 23:38, 28 July 2006 (UTC)

[edit] The December 2003 model predictions vs. actual data

Is this section really relevant anymore? I think we've established sufficiently that the 2003 predictions were way low, and continuing on a monthly basis to show how much more mighty we are than we thought we'd be doesn't seem to be productive. it's absolutely stunning historical data, but at this point it's about 50% out of sync. Maybe a new prediction is in order? -- nae'blis 20:02, 31 August 2006 (UTC)

• I removed this section. I agree with you. It does not have any sense to show that the statistics once calculated in 2003 do not hold anymore. Diego Torquemada 12:59, 8 November 2006 (UTC)

[edit] Logistic growth model

Just after en.wikipedia reached 1 million articles I predicted here that there is a maximum in articles in the form of a cumulative gauss (or Logistic function). In less than a year the top of articlegrowth is now probably reached. The 2nd derivative is now convingingly below the x-axis, the indication that the top of article growth is reached.

My model which still holds for about a year and has proven to be quite predictive:

• The top of articlegrowth is now (end of February 2007) probably reached, at about 60000 new articles a month.
• The maximum of articles on en.wikipedia will be about 4 million articles.
• This maximum will be reached in 2013

Could anyone doublecheck my model. HenkvD 20:34, 28 February 2007 (UTC)

I find your model interesting, and perhaps more believable from a real-world perspective than the purely exponential models proposed hitherto. I'm not really a mathematician though, so I wouldn't presume to be able to verify it. Torgo 06:39, 16 March 2007 (UTC)