# Requirement change

Feedback from the last review round: an agent's very first rating from months ago is still
weighed exactly the same as the one they got this morning, and that is not what anyone wants.
The score should lean toward how an agent is doing lately.

**The rule the product side wants:** every time a new rating comes in for an agent, blend it with
that agent's current average using a straight 50/50 split — the new rating counts for half, and
everything the agent had built up before counts for the other half. So an agent sitting at a
perfect 5.0 average who gets rated 1 star next should immediately drop to 3.0, not barely move.

A worked example, so nobody has to guess the rounding: an agent's first rating is 5, so they are
at 5.0. Their second rating is also 5 — 5.0 blended with 5 is still 5.0. Their third rating is a 1
— 5.0 blended with 1, half and half, is 3.0.

A few things that do not change, because someone always assumes they do:

- **The 1-to-5 scale is unchanged**, and an out-of-range or blank rating is refused exactly as
  before.
- **The rating count still goes up by one for every rating**, whichever way the average moved. A
  low count is still a low count — this is about the average, not about how much evidence backs
  it.
- **The leaderboard's tie-break rule is unchanged**: highest average first, then more ratings,
  then agent id.
- This is a brand-new kind of system, not a change to the one that already exists — whatever
  system a caller already built still behaves exactly as it always has.
