Both Teams To Score is a binary market: either both sides score or they do not. The model estimates the probability of each team finding the net at least once, combines those into a single BTTS Yes probability, and the No probability is everything that remains. The two sides always sum to 100%, so an edge on one side means there is no edge on the other at fair prices.
Which outcome is more likely and where the value sits are separate questions. If the market has priced Yes too short because a fixture looks like a goal-fest, the No side can carry the positive expected value even when Yes remains the more probable outcome. The fair odds column shows what the model believes each side is worth; the +EV figure shows the gap between that and the price available. This is why the analysis can recommend BTTS No on a fixture that looks attacking on the surface.
The BTTS estimate comes from the same engine as the goals markets: each team’s expected goals in the fixture, converted into the probability of scoring at least once. A side with strong overall xG concentrated in a few big chances can still carry a real blank risk, and a modest side facing a leaky defence can be more likely to score than their reputation suggests.
Some fixtures show no edge on either side of BTTS. That is a normal result: the market has priced the fixture about right. The same discipline applies here as anywhere else on the platform: look for the Sanity Score and +EV thresholds to line up before acting, and skip the fixture when they do not.