Can we make it 5?

This follows up on the four dimensions in two dimensions post. I updated the graph adding some functionality, increasing the readability and improving the aesthetics. Moreover, the plot can now transition from a visualization with two categorical variables to one with four. The principle guiding the creation of the graph remains the same: to display as much information as possible into a two-dimensional graph without sacrificing interpretability and maintaining (hopefully) pleasing aesthetics. Because of the addition of the transition effect, I thought it was like adding a new dimension to the four which already existed. Below I describe the implementation of these additions. The graph is made in d3.js and the final plot can be admired here.

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Web-interface for Delphi Method III

This post is the third in the series describing the web-interface I created to administer a questionnaire with the Delphi method. In this post I describe the code used to give feedback to the participants in round 2 of the Delphi study on functional magnetic resonance imaging on tinnitus. If you are interested in the previous posts, this post describes the interface for round 1 whereas this post describes (the first part of) the interface for round 2.

Four dimensions in two dimensions

This scatterplot is one of the best data visualisation I made. I like it because it concentrates a lot of information into a single visualisation. The scatterplot displays four dimensional data (i.e., four variables) using a two dimensional scatterplot. I made the first implementation in R, but because I wanted to add interactivity I switched to d3.js. Below I describe the choices I made to display the information and how I coded them in d3.js.

Visualizing participants performance [wbwit III]

This is the third post on the development of a web-based word identification task. See this post for the implementation of the word identification task and this post for uploading the participants results to the server. This post describes how to plot the

Uploading data to the server [wbwit II]

Uploading the data gathered from the web-based version of the word identification task (i.e., lexical decision – see this post) to a MySQL database was more challenging than expected. The problem is that there is a limit on the size of data which could be transfered with an ajax XMLHttpRequest (ajax call from now on) from the web-page to the host server. It took quite a bit of trial-and-error to discover that the problem was

Web-based word-identification task [WBWIT I]

A method to collect a massive amount of experimental data on cognitive human behavior is every experimenter’s dream. Not having to sit in the lab waiting while a participant is performing the task or the possibility of having multiple participants completing the task at once are only two of the main advantages. However,