The Top 3 tracker is a long view of the contest, trying to figure out who will end up in the Top 3 based on the current standings. It works in a similar way to the finals model, but rather than week-to-week, it looks at historical information to decide who most looks like a Top 3 contestant.
To visualize the historical data, I have plotted as points the model elimination probability versus whether or not the person made the Top 3. If the person is near the top, he or she made the Top 3, and if that person is near the bottom, he or she did not make it. Some vertical jitter has been added so that points can be easily seen. Mouse over a dot to see which person in Idol history it corresponds to.
People in the bottom left were thought to be sure finalists, but didn’t make it. This includes people like Siobhan Magnus, Chris Daughtry, Brooke White, Thia Megia, and Pia Toscano. The lower right is people who never had a shot. The upper right is people who were unlikely to make the Top 3, but did: Haley Reinhart and Syesha Mercado are the most prominent examples. The upper left are front runners who did indeed make the Top 3. Currently, nobody has a better score than the lowest person ever not to make the Top 3 (Siobhan) and nobody had a lower chance that the highest dark horse (Haley).
The black line is the theoretical curve of probability of making it versus how likely someone was to be voted off in the first finals round (called Round 2). At this point, it’s still very uncertain who will make it, and the Top 3 tracker hasn’t yet been able to start averaging the data to get a better picture. As the season goes on, the system becomes more sure of itself.