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Grade accuracy: the prediction against the grade received

Every pre-grade is an estimate. This page measures how close those estimates come to the grades collectors actually receive, company by company, and sets out the method in full.

In short

GradeMate measures its accuracy by comparing, for each grading company, the grade predicted from photos with the grade users report receiving from that same company for the same card. A company's figures (mean absolute error, share of results within half a grade, share of exact grades) are published only once 30 eligible results have been collected; below that, the table shows how many have been collected so far. The grades received are self-reported by users and are not verified against certificates.

Estimate my grade

01 — Results

Results by grading company

The predicted grade compared with the grade users report receiving from the same company. Recalculated every day.

No grading company has reached 30 results yet, so GradeMate does not publish an accuracy rate. Each row shows how many results have been collected so far.

  • PSAResults · 0

    Collecting data — 0 of 30 results

  • BGSResults · 0

    Collecting data — 0 of 30 results

  • CGCResults · 0

    Collecting data — 0 of 30 results

  • SGCResults · 0

    Collecting data — 0 of 30 results

  • PCAResults · 0

    Collecting data — 0 of 30 results

  • TAGResults · 0

    Collecting data — 0 of 30 results

  • HGAResults · 0

    Collecting data — 0 of 30 results

  • Calculated on 30 September 2026. Grades are self-reported by users and not verified against certificates. A company's figures are published once it reaches 30 results.

02 — Key facts

The method at a glance

What is compared
The predicted grade and the grade received, from the same company
Where the grades received come from
Entered by users, not verified against certificates
Publication threshold
30 eligible results per grading company
Earliest grade counted
Entered at least 14 days after the card was saved
Measures
Mean absolute error, within half a grade, exact grade, average difference
Updates
Recalculated once a day

03 — Details

What counts as a result

A result is one saved card whose grade has come back from the grading company. Each rule below removes a case where the comparison would say nothing about the estimate.

An analysis GradeMate can vouch for

The card must have been saved straight from an analysis run on GradeMate, which the server records at the time of the analysis. Cards saved before that record existed are left out: nothing proves which prediction they came from.

The same grading company

Each prediction targets one company's scale. A grade received from another company stays in your collection but is left out of the figures: comparing a PSA prediction with a CGC grade would measure the gap between two scales, not the error of the estimate.

A conclusive analysis

When the photos do not allow a reliable estimate, the report says so and gives no grade. With no prediction there is nothing to compare, so these cards never count.

An unlocked detailed report

Results follow the same rules as the +1 credit offered for entering a grade, so that every grade in the figures has gone through the same checks. A card whose detailed report was never unlocked is not counted.

Entered at least 14 days after saving

Grading takes weeks. A grade entered within 14 days of saving the card cannot be the grade the company returned for it, so it is ignored. Changing a grade later dates it again, and the 14-day rule applies to the new date.

One result per card, while the card exists

A card counts once, whatever the number of times its grade is edited. A card deleted from a collection leaves the figures at the next daily calculation.

04 — Details

How to read the figures

Results

The number of cards that meet every rule above for that company. Read it before any other column: the same percentage means more on 300 results than on 30.

Mean absolute error

The average gap between the predicted and the received grade, in grade points, whichever the direction. 0.50 means the prediction is off by half a grade on average; 0.00 would mean every prediction was exact.

Within half a grade

The share of results where the received grade is no more than half a point away from the prediction: a predicted 8.5 followed by a PSA 8 or a PSA 9 counts; a PSA 7 does not.

Exact grade

The share of results where the two grades are identical. It is the strictest measure: on a scale in half points, a prediction can miss the exact grade while being only half a point away.

Average difference

Predicted minus received, averaged with its sign. Positive means the estimates run high, negative means they run low. A value close to zero next to a large mean error means the misses go both ways.

Grades entered

The dates of the first and the last result counted, so you can tell whether a company's figures describe last month or last year.

05 — Key points

What these figures cannot tell you

Publishing a measurement means publishing its limits. These are the ones that matter most here.

Grades are self-reported

Users type the grade they received. GradeMate does not ask for the certificate number and does not check the company's database, so a typing error or an invented grade is not detected. The rules above only remove grades that cannot be real.

Not every card is reported

Collectors may be more inclined to enter a grade when it matches the prediction, or when it disappoints. The figures describe the results that were entered, not every card that was analysed.

Grading itself varies

Grading involves human judgement, and the same card submitted twice can come back with different grades. Part of any gap belongs to the grading, not to the estimate.

A photo is not the card in hand

The estimate sees what the photos show. A defect that a photo does not reveal, such as a faint surface scratch, shows up in the grade received but could not be in the prediction.

The edges of each scale

The grade field accepts 1 to 10 in half points, and PSA has no 9.5. PCA's 10+ is entered as 10, so it is compared as a 10.

Small samples move

Even at 30 results, a single card shifts a percentage by more than three points. Read the number of results next to each figure before comparing two companies.

06 — Steps

Add your own result

Every grade entered makes the figures more useful for the next collector deciding whether to submit a card.

  1. Analyse and save the card

    Run the analysis on GradeMate, choosing the company you plan to use, and save the card to your collection from the report.

  2. Submit it for grading

    Send the card to the company you chose at analysis. A grade from another company is kept in your collection but not counted here.

  3. Enter the grade received

    In My collection, type the grade on the card's tile, in half points. You can change or clear it later.

  4. Receive +1 credit

    From 14 days after saving, the first grade entered for a card with an unlocked detailed report earns one credit, once per card and at most 3 a month.

07 — Questions

Frequently asked questions

What is GradeMate's accuracy rate?

It depends on the grading company, and GradeMate publishes a company's figures only once 30 eligible results have been collected for it. The table at the top of this page shows the current figures, or how many results have been collected so far.

Are the grades checked against the certificates?

No. The grades received are entered by users and are not checked against the grading company's certificate or database. The rules on this page remove entries that cannot be real results (entered too early, from another company, with no prediction to compare), not entries that are false.

Why wait for 30 results?

Below a few dozen results, one or two unusual cards move a percentage by several points, and a rate calculated on ten cards would be noise presented as a measurement. GradeMate has set the threshold at 30 results per company; until a company reaches it, its row only shows its progress.

Why doesn't a grade from another company count?

The prediction is made on the scale of the company chosen at analysis, and scales differ: a PCA 10 is not the equivalent of a PSA 10, for instance. Comparing across companies would mix the error of the estimate with the difference between two scales.

Does entering a grade change my card's report?

No. The report keeps the prediction made at analysis. The grade received is stored next to it, with the company that awarded it and the date it was entered. You can change or clear it at any time; a credit already received stays yours.

Can one collector skew the figures?

The figures count cards, not people: a collector who grades twenty cards contributes twenty results. Credits for entering grades are capped at 3 a month, which limits the incentive to enter grades for the sake of it.

Estimate your card's grade

Then submit it, enter the grade you get back, and add your result to this page.