When answering the question "how much do you spend gambling?", gamblers tend to provide inaccurate answers. Players are more accurate in estimating short-term performance but less accurate when measuring their long-term betting results. As a matter of fact, highly involved players would be less accurate when measuring their own performance than less engaged ones.

When analyzing gambling behavior, it could be a good practice to segment players based on gender, age, and gambling type, as behavior can significantly differ between these groups.

The degree of bias, for example, can be different depending on the gambling type (e.g. fast-pace live-betting vs season-winner bets).

Gender and age did not seem to have a big impact on gambling cost estimation bias. Yet, these could be useful when aiming at foreseeing problem gambling.

In general, most gamblers are capable of estimating if they won/lost after one month of betting. However, gamblers with higher losses seem to experience difficulty estimating their actual expenditures. In addition, frequent players also appeared to have trouble accurately measuring their own gambling outcomes.

A limitation of this study: the participation in this study was promoted on the gambling provider's website and the sample could have been over-represented by players who intensively visit the website. In other words, participants could have appeared to be part of frequent players in the risk group.