Montag, 27. Oktober 2014

Causal inference, again.

Alles, was du schon immer über causal inference wissen solltest, aber nicht gefragt hast:
  1. Causal inference, ein neues Buch von Hernan und Robins (PDF, Code in STATA, R, ...)
  2. Measuring causal effects in the social sciences, ein Kurs auf Coursera (Videos, Quizzes...)
  3. XKCD über selection effects:

Freitag, 26. September 2014

Foundations of Data Science

John Hopcroft and Ravindran Kannan share their draft of "Foundations of Data Science". It is clearly a more formal treatment of the topic than you will find in the other books and lectures that I mention here, but for those of you who are interested in the algorithmic and mathematical foundations, it could be a great resource. The draft covers a variety of topics, including singular value decomposition, random graphs and small worlds, clustering, belief propagation and algorithms for massive data problems.

The future of computer science is data. Have fun!

Big Data, Analytics, Networks, and Predictive modeling

The latest edition of Information System Research has an editorial by Ritu Agarwal and Vasant Dhar, who discuss IS research in the emerging areas Big Data, Analytics, Data Science, Network Science, and Predictive Analytics.

Data science, randomized controlled trials and networks are rapidly changing what we can study and how we can study it.

This is yet another wake-up call to the IS community. But who is listening?

I fully agree with what is being said in this piece, and I urge you to read it carefully.

Mittwoch, 3. September 2014

6 degrees of separation in the boardgaming industry

In my introductory course on network science I usually use the popular "Hollywood actor network" to introduce students to the topological characteristics of social networks. This network is the basis for the Kevin Bacon-game, where you try to get from any actor to Kevin Bacon, by movies that they have appeared in together.

The Hollywood network is great (and a classic), but I prefer a game night over a movie night. Also, I like the idea of using networks to describe relationships between products in an industry. Long story short, I have constructed a Boardgame Network where boardgames are connected by the people who create them (artists and designers). This site is basically for my students, but others might find the idea interesting as well.

You can explore the Boardgame network here.

A PDF with statistics and images is here.

Freitag, 22. August 2014

German soccer: A network summary

This network shows the results of every soccer match played in the German Erste Bundesliga from 1963-2014. Click to enlarge. A high-resolution PDF is also available.

Montag, 18. August 2014

The network structure of scientific collaboration in the journal Business & Information Systems Engineering and its predecessors

This picture shows the network of coauthorship in the scientific journals Business & Information Systems Engineering and its predecessors. As a result, you see mostly German IS researchers. The original data consists of thousands of authors, here we show only the largest connected component. Color, node layout and edge width were used to show who is working with whom.

Here is a high-resolution PDF

Please Email me if you have questions concerning the data or the network.

Dienstag, 12. August 2014


There are curves of constant width besides circles and spheres

And they can be used to drill a square hole: