CrossValidated launched!

The Cross­Val­i­dated Q&A site is now out of beta and the new design and site name is live.

New design

The new design looks great, thanks to Jin Yang, our designer-​​in-​​residence. Note the nor­mal den­sity icon for accepted answers and the site icon depict­ing a 5-​​fold cross-​​validation (light green for the test set and dark green for the train­ing set). There is a faint back­ground graphic in the header and footer from a pro­gram that tracks and plots a person’s mouse move­ment. This gives the sug­ges­tion of ran­dom­ness as well as the idea of data visu­al­iza­tion (another topic cov­ered on the site).

Name and URL

The URL cross​val​i​dated​.com will work, but re-​​directs to stats​.stack​ex​change​.com. The Stack­Ex­change team (who host the site and pro­vide all the archi­tec­ture) wanted the site to be a sub­do­main of stack​ex​change​.com. How­ever, at least we got the name CrossValidated.


The site is intended for use by sta­tis­ti­cians, data min­ers, and any­one else doing data analy­sis. It cov­ers ques­tions about

  • sta­tis­ti­cal analysis
  • data min­ing and machine learning
  • data visu­al­iza­tion
  • prob­a­bil­ity theory
  • sta­tis­ti­cal and data-​​driven com­put­ing (e.g., ques­tions about R, SAS, SPSS, Stata and Minitab)

The inclu­sion of data min­ing and machine learn­ing along with sta­tis­tics and prob­a­bil­ity was a delib­er­ate attempt to get these two com­mu­ni­ties to talk. We work on sim­i­lar prob­lems, but often with dif­fer­ent tools and dif­fer­ent per­spec­tives. I hope the site comes to be widely used within both com­mu­ni­ties. In fact, I hope that we can even­tu­ally stop talk­ing about two com­mu­ni­ties and just refer to the “data sci­ence community”.

My orig­i­nal idea was that this would be help­ful to researchers strug­gling with data analy­sis issues but have no sta­tis­ti­cian to ask for help. University-​​based sta­tis­ti­cians are often inun­dated with requests for help from researchers in other dis­ci­plines who have no quan­ti­ta­tive train­ing but need to do apply some sta­tis­ti­cal techniques.


For those who haven’t been read­ing this blog, I pro­posed this site on 15 April 2010. The scope of the site was deter­mined via a com­mu­nity process, then we went through a phase of build­ing a suf­fi­cient com­mu­nity. The beta site was launched on 19 July 2010 with the first ques­tion on “Elic­it­ing pri­ors from experts”.

The site was offi­cially launched today (5 Novem­ber 2010). So it took just over 200 days from pro­posal to launch — I had no idea what I was start­ing, but I’m glad it worked out! There are now 1048 ques­tions and 1763 users which is a great start. But there must be hun­dreds of thou­sands of peo­ple doing data analy­sis and who would really ben­e­fit from a site like this. So please spread the word about Cross​Val​i​dated​.com.

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  • Jeromy Anglim

    Great Work! The site sat­is­fies an impor­tant need. I’ve learnt a lot by ask­ing and answer­ing ques­tions on the site. And I’ll be rec­om­mend­ing it to the research stu­dents that I consult.

  • Tal Galili

    Won­der­ful suc­cess, I find the site of great use.

    Thanks again Rob for all your energy and thought that was put into this!