Alt Value is calculated by using a combination of data and systematic market knowledge. When we have a lot of data (e.g., base prizms), the value will be more similar to the average of recent transactions. However, when data is sparse, we leverage comparables and use them as anchors to price the card, similar to how an expert in the hobby would do so themselves.
We really appreciate it when you flag any values that look off. The incorrect value may be due to updates to our valuation model, which can sometimes cascade to cards for which we already have data points. We're asking our customers to let us know incorrect price data through the messenger using the 'Alt Value looks off' button that can be found when starting a new conversation. Our experts will rerun the flagged assets through Alt Value, and we'll give you an update when the change is reflected.