The Bandwagon Index
A weekly, per-league measure of how confident the crowd is in each team, computed from the stances people take in the app. Method version 1.
Inputs
Every take in Bandwagon is ▲ or ▼ on one $tag, and every person gets one stance per tag per day. Each stance is stamped fan (the person declared the team as theirs) or neutral (they did not) at the moment it is made. House persona accounts and banned accounts are removed before anything is counted. The daily counts per tag and segment are the sentiment endpoints; the Index is built from them.
Week
Monday to Sunday, UTC. The Index for a week is computed once the week is complete and is not revised afterwards. week_start is the Monday.
Confidence
weight(age) = 0.5 ^ (age / 3.5) age = 0 on Sunday … 6 on Monday
confidence = 100 · Σ weight·up / Σ weight·(up + down)
sample_size = Σ (up + down) unweighted: people, not postsA half-life of 3.5 days means Sunday counts fully and Monday about a quarter: the number leans toward how the week ended. 50 means weighted ▲ and ▼ were equal. It is computed separately for neutrals (the headline) and fans.
Minimum sample
25 people in the segment over the week. Below it the confidence is null and the team is not published that week; the sample size is still reported. The fan number appears only when the fan sample meets the threshold too.
Derived numbers
| field | meaning |
|---|---|
gap | fan confidence − neutral confidence, when both are published. Positive: the fans are more confident than everyone else. |
move_7 | neutral confidence this week minus the same calculation for the seven days ending one week earlier. Null when that window is below the threshold. |
move_30 | the same, against the seven days ending 30 days earlier. |
rank | published teams ordered by neutral confidence; ties broken by the larger neutral sample, then name. |
movers | the five largest positive and five largest negative move_7 among published teams. |
Worked example
| day | age | ▲ | ▼ | weight |
|---|---|---|---|---|
| Mon | 6 | 10 | 10 | 0.305 |
| Wed | 4 | 8 | 4 | 0.453 |
| Sun | 0 | 20 | 5 | 1.000 |
confidence = 100 · 26.67 / 36.53 = 73.0, sample_size = 57. The raw share of ▲ over the week was 66.7; the decay pulls the number toward the latest day.
What it is not
Not a prediction, not a power ranking, not a betting signal, not a grade of any person. It measures how confident people sound about a team this week, weighted toward the end of the week, among people who are not its fans. That is why the sample size is on every row.
method_version).