IndexFair › Methodology › Source weighting
Each source contributes to a score by a fixed trust weight. The spread of that evidence becomes the ± interval — the score is a point, the interval is the honesty around it. The confidence label shown next to it is a separate signal: it is set from how much evidence has been collected, not from this interval's width.
Trust weights are fixed per source tier and applied before aggregation — they do not change with a brand's score, cannot be overridden per brand, and are published configuration. A wider confidence interval means less agreement across sources or fewer effective sources, not a worse brand. The confidence label (Normal, Low, Emerging, or Insufficient) is computed separately, from how much evidence has accumulated — it is not derived from this interval, and the two can move independently: a brand can carry a narrower interval than another brand while still showing a less favourable confidence label, or the reverse.
What ± means. 7.2 ±0.5 says the index very likely sits in 6.7–7.7. A wider interval means less agreement or less evidence — never a worse brand. Affects: the ± on every score. The confidence chip beside it is a different signal — how much evidence has been collected — computed independently of this interval.
All figures are illustrative. The interval of ±0.5 reflects the spread across the three sources — not a failing grade.
