asking_vs_appraisal_pct = (Avena median asking €/m² − official appraised €/m²) / official appraised €/m², in percent, rounded to 0.1. Positive means the asking median sits above the appraisal. Derived by Avena from the two inputs. It is not an official statistic.
yield_spread_pp = Avena median gross yield minus the implied flat gross yield, in percentage points, rounded to 0.1. The implied yield is (SERPAVI median monthly rent per m2 times 12) / Avena median asking per m2, times 100. A blank Avena yield or a blank implied yield leaves the spread blank. The Avena yield is the short-stay estimate on the listings. The implied yield lays a habitual-residence rent on a new-build asking price.
The headline is the median of the gaps that exist for that layer. An even count uses the mean of the two central values, rounded to 0.1. A place with a missing side is left out of the median and shown as missing. The median is not weighted by listings.
A gap widened when the absolute value of the current gap is larger than the previous snapshot of the same gap. A snapshot counts only when an earlier gap for that place is passed in. The committed official files do not store an earlier Avena asking median beside an earlier official benchmark, so the live summary passes none and marks nothing as widening.