Research by scholars Zakary Tormala, Jayson Jia, and Michael Norton has examined how people perceive those with high promise/potential. Tormala explained their findings in an article on "Insights by Stanford Business."
In a series of experiments set in different contexts, we found that high potential can be more appealing than equally high achievement. Our studies uncovered this in situations ranging from basketball player evaluations to hiring decisions, to salary offers, to grad school admissions recommendations... In general, potential seems to engender greater interest than achievement. It was counterintuitive to us too at first. It seems objectively more impressive to actually achieve something great than to have mere potential to do so. But there is a fairly robust finding in the psychological literature that uncertain events and outcomes can stimulate greater interest and information processing — more thought — than more certain ones. So when potential is being compared with achievement, the uncertainty surrounding potential can make it more engaging, or maybe even pleasurable, to think about. It's as if people engage more as they try to work through the uncertainty and figure out what the truth will be... In most of our studies we tried to equate the level of potential and achievement. For example, in one study we showed the exact same (impressive) stats for a hypothetical NBA basketball player and merely described those stats as predictions or as actual performance records. We found that participants thought the player was more likely to end up an All-Star one day when they'd seen predicted rather than actual stats.
The authors argue that these findings have substantial implications with regard to talent management decisions. I strongly agree. They also contend that small changes in wording can matter a great deal, perhaps in a recommendation letter that you provide for someone. Talking about their potential can be even more impactful than rattling off their past achievements.