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October « 2009 « MyChances.net

Archive for October, 2009

Scatterplots: Now showing predictions, acceptance status

by James
Sunday, October 18th, 2009
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Tonight I added a couple of features to the scatterplots (scatter charts / scattergrams) that I introduced in my last post. The two new variables that you can now access are: acceptance status and prediction.

Let’s say you wanted to know how accurate our prediction engine is within one particular range of predictions. For example, you want to see what really happens when we claim someone has around 80-100% chances. Set the axes to Prediction, add a small amount of jitter, and you can now get a sense of how many miscategorizations we’ve made in that region. Take a look at Boston College to see an example.

You can now graph our predicted probability of acceptance on scatterplots.

You can now graph our predicted probability of acceptance on scatterplots.

Clearly we do a pretty good job at Boston College. For one, you can instantly see that the blue (accepted) applicants cluster on the right side with high predictions, while the red (rejected) cluster on the left. Additionally, look at the mean (average) lines. The mean prediction for accepted members was 83.3%, while that for rejected members was 35.6% – a very large difference.

Another way to visualize the data would be to set one axis to Accepted, and another to Prediction, so you get perfect separation between the blue (accepted) and red (rejected), and can perhaps more easily see how well our predictions separate the accepted from the rejected at any particular range of chances.

These updates were requested by Christian Romero; thanks, Christian.

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New college admissions tool: Interactive flash scatterplots

by James
Sunday, October 4th, 2009
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We have rolled out our interactive flash scatterplots (also known as scattergrams), available on every college page under the ‘My Analysis’ tab.

These graphs display the accepted and rejected applicants scattered across a 2D canvas according to the variables that you choose. For example, you might look at Unweighted GPA & SAT, or Instate & Average AP Score. To get started with this new tool, see Cornell’s scatterplots.

For any given SAT score, valedictorians appear more likely to get into Cornell than non-valedictorians.

For any given SAT score, valedictorians appear more likely to get into Cornell than non-valedictorians.

Because there are many, many overlaps, you can set a level of jitter, so each point floats near its true value. For example, if you look at Unweighted GPA and Valedictorian Status, everyone will clump on top of one another. (You either are a valedictorian, or you aren’t, so there are only 2 slots that you might possibly fit into – hence lots of clumping.) If you set a 20% jitter to Valedictorian Status, things will spread out nicely, so you can see what is really going on.

With your feedback and criticism (please post it here or in the forums), we’ll work on improving the tool. Enjoy!

These display the accepted and rejected applicants on the same canvas. You can choose which dimensions they’ll be displayed against (unweighted GPA and SAT, for example).
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