Identifying cheaters in test results, a simple method

Jonathan Dushoff had issues with students in his population biology class cheating on his exams. One year there was suspicious behavior, but Dushoff and the proctors weren’t able to prove the students cheated as it happened. So he looked closely at the test results to find the guilty students.

… No pair of students did this, but there were four outlying pairs that got close, shown in red. And looking back at the seating arrangements, in a class of 200 students, all four pairs were students who sat adjacent to each other.

Dushoff has since gone back to multiple exam versions.

Reference: Identifying cheaters in test results, a simple method



They are as good as LEGO can do, I guess.


How to learn R: A flow chart

I often find myself giving people suggestions about how to learn R, so I decided to put together a flow chart. This is geared toward typical psychology or cognitive science researchers planning to do basic data analysis in R. This is how to get started — it won’t make you an expert, but it should get you past your SPSS/Excel addiction. One day I’ll expand it to include advanced topics.

Reference: How to learn R: A flow chart

Gartner 2015 Magic Quadrant

It is quite interesting how Microsoft jumps from a niche player to a visionary after it purchased Revolution Analytics, a company of R.


Bayes’ Theorem with Lego

What’s a good blog on probability without a post on Bayes’ Theorem? Bayes’ Theorem is one of those mathematical ideas that is simultaneously simple and demanding. Its fundamental aim is to formalize how information about one event can give us understanding of another.

Reference: Bayes’ Theorem with Lego

Outlier Detection on Big Data

Finally, someone is looking at outlier detection of Big Data.

Outlier detection can be a pain point for all data driven companies, especially as data volumes grow. At Netflix we have multiple datasets growing by 10B+ record/day and so there’s a need for automated anomaly detection tools ensuring data quality and identifying suspicious anomalies. Today we are open-sourcing our outlier detection function, called Robust Anomaly Detection (RAD), as part of our Surus project.

Reference: Outlier Detection on Big Data

2015 Social Media Map: Updated Guide with Live Links

The world of social media can be a vast and overwhelming place. To help you find your way, Overdrive Interactive has updated their popular Social Media Map which provides a comprehensive index to all things social media.

The downloadable “map” includes everything from social media networks to social media listening tools to link shorteners and social commerce. It even has categories for social music networks and social gaming sites. If it falls under “social media,” chances are you will find it here.

For the experienced social media user the map provides a quick cheat sheet filled with bookmarks to a wealth of tools and information. For those new to social media, it offers an opportunity to explore a number of new platforms, tools and audiences.

Reference: 2015 Social Media Map: Updated Guide with Live Links