The IQ score answers a single question: how investment-grade is this cultural artefact? It rates four dimensions, each scored 0-100 against a published rubric. The framework underpins every DIG study, the interactive scorer, and the evidence we collect for USPAP-compliant appraisals.
Auction prices tell you what one bidder paid on one day. They do not tell you whether the price will hold, whether the provenance is defensible, or whether the item can be resold without a 30 percent haircut. The DIG IQ score separates investment quality from spot price by rating the underlying evidence directly.
Two items can sell for the same dollar amount and have very different IQ scores. A signed photograph with a single-source dealer COA might fetch $40,000 next to an auction-house-vouched lot at $40,000, but only one is defensible in an estate filing or insurance dispute. The score makes that distinction visible.
Each sub-score is graded 0-100. The overall IQ is a weighted average. Provenance and Delta carry equal top weight at 30% — provenance because nothing else matters without it, Delta because tracked appreciation versus auction estimate is the differential signal that distinguishes cultural assets that hold value from those that don't. Verification and Liquidity sit at 25% and 15% respectively.
Strength and documentation of the chain-of-custody. Was the item acquired directly from the artist, estate, or instrument tech? Is there contemporaneous photographic or film evidence of use? Without P, the other scores are meaningless.
Authentication corroboration. Multi-source verification, handwriting comparison, materials testing where applicable. Single-source dealer COAs cap the V-Score at 60. Largely a gating dimension — items either authenticate or don't.
Resale market depth. How many comparable sales in the last 5 years? How many qualified buyers? Is there a documented repeat-sale history for the asset class? Modifies the score; rarely makes or breaks it.
Performance against pre-sale estimate, tracked longitudinally. The signal DIG uniquely surfaces — the others can be sourced from any specialist. A high D-Score indicates the market is consistently paying for cultural value the trade systematically under-prices. This is where DIG adds the most.
Every IQ score sits in one of five named bands. Bands map to risk-adjusted positioning, not to predicted dollar value.
| Band | Score | Meaning |
|---|---|---|
| Generational | 90-100 | Singular, multi-source verified, deep liquidity, extreme estimate outperformance. Defines the category. Cobain Mustang, Hendrix Woodstock Strat tier. |
| Investment | 75-89 | Strong provenance, clean verification, active resale market. Suitable as a portfolio anchor. Most Irsay and Gilmour pieces sit here. |
| Collector | 60-74 | Solid item with documented but narrower provenance. Resale demand exists but buyer pool is shallower. The bulk of the secondary market. |
| Speculative | 40-59 | Weak or single-source provenance, thin liquidity. Buy at your discretion, do not insure or estate-plan against this number. |
| Decorative | 0-39 | Anecdotal attribution, no defensible chain-of-custody. Treat as a piece of memorabilia for personal enjoyment, not an asset. |
Three published studies show the framework in action across different evidence profiles.
Defining cultural moment (P), multi-source verified (V), proven repeat-sale demand on the Mustang and Unplugged cardigan (L), median 8.4x estimate multiplier (D). The combination is rare. Read the full study →
Single-owner sale isolating one artist's performative provenance (P, V). Active but specialised resale market (L). Median 6.8x estimate multiplier across 126 lots (D). Read the full study →
Documented portfolio cost basis enables true return attribution. Read the full study →
Important distinction: the IQ score is editorial. A USPAP-compliant appraisal is a legal document. They use overlapping evidence but answer different questions, and DIG Appraisals employs both methodologies.
| DIG IQ Score | USPAP Appraisal | |
|---|---|---|
| Question answered | How investment-grade is this? | What is the legally defensible fair market value? |
| Output | 0-100 score with sub-scores | Written report with single dollar figure |
| Used for | Editorial, advisory, screening | IRS, insurance, courts, donations |
| Legal standing | ~ | Full, when prepared by qualified appraiser |
| Evidence base | Provenance, verification, comps, deltas | The same, plus formal report and witness |
The IQ score is not a price prediction. A score of 96 does not mean an item will sell for more than a score of 80. It means the underlying evidence is stronger and the asset is more defensible against post-sale challenges.
The framework also does not replace expert judgement. Two qualified appraisers may grade the same V-Score within a 5-point range; the rubric narrows the spread but does not eliminate it. The score's value is reproducibility and transparency, not algorithmic certainty.
Use the DIG IQ tool to screen an item in seconds. For a USPAP-compliant valuation suitable for IRS, insurance, or estate purposes, contact Helen directly.