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.
All things being equal, everyone’s chances should improve every week, as any time someone is eliminated you have a better chance just by random pick.
Alex Preston has taken over the top spot, after a week where he got rave reviews. The current Top 10 has six people who’ve been in the bottom 3 or were wildcard, but he isn’t among them. He’s improved his chances each week.
Sam and Majesty were at the top of the heap, but have now fallen. This is logical, since they were both in the bottom 3 this week. They each still have a good chance of making it, though. The same goes for Jena.
Now we look at the Top 3 tracker over time:
You can see Alex rising from an initial 27% to his current 60% chance. Majesty rose slightly to be even with Jena, who fell a bit since last week. Sam is up, though he was in the bottom 3. He will likely be trying harder from now on, so this might still be correct. Caleb is flat, while Jessica fell sharply on an awful performance (she was nonetheless safe).
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.
Alex has a better score than anybody who didn’t make the Top 3 (Siobhan Magnus), meaning that it would be a new record if he didn’t. Dexter, M.K., and Malaya all had a score worse than the worst who did make it (Haley Reinhart), meaning that it would be quite surprising if they did.
The black curve is the theoretical probability of making it versus how likely someone was to be voted off in the Top 11 (called Round 3). 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 (averaging the data yields no improvement at this point). As the season goes on, the system becomes more sure of itself, as averaging the data gives a much better fit.