On-card versus sticker autographs
Sets and products. . 1 min read.
A signed card carries the signature in one of two ways, and collectors do not value them equally.
On-card
The player signed the card itself. The signature sits on the card surface, interacts with the design, and cannot be separated from it. This is what collectors generally prefer and pay more for.
Sticker
The player signed sheets of clear stickers, which the manufacturer later applied to cards during production. You can usually see the sticker edge under angled light.
Why manufacturers use stickers at all
Logistics. Getting sheets of stickers signed does not require the cards to exist yet, does not require shipping valuable printed cards to a player, and does not risk a card being ruined by a poor signature. For a set with dozens of signers across several countries and a fixed release date, it is often the only workable method.
A sticker autograph is not less genuine. The player signed it. The premium on on-card is an aesthetic and collector preference, not an authenticity judgement.
Pricing them
Treat them as different cards when reading comps, in the same way you would treat different parallels. Mixing on-card and sticker sales into one average produces a figure that describes neither, exactly as warned in how to price a sports card.
For signatures obtained outside a manufacturer product, authenticity becomes the whole question. See how to spot a fake autograph.