Gerhard Berger has said that it is difficult to judge the potential of young drivers based on this week's testing in Hungary.
After the post-race running at the Hungaroring, veteran F1 commentator Martin Brundle declared: "There's some very exciting young talent knocking on F1's door."
However, F1 legend Berger told APA: "The teams all use different strategies.
"McLaren, for example, sent Lando Norris out every time with empty tanks."
Berger's own nephew Lucas Auer was also testing in Hungary, and the former McLaren and Ferrari driver said: "I think Lucas was able to show what he could do."
What comes next for Auer, however, is very unclear. The 22-year-old drives full time in the German touring car series DTM, but his employer Mercedes have just announced their departure after 2018.
"Of course that complicates the situation," Berger, the DTM series boss, admitted.
Mercedes are leaving Formula E to join a host of carmakers in Formula E, but Berger is not sure the all-electric series would be the right move for Auer.
"If a driver has to go from one car to another after a few laps, it's a demo rather than a race, but maybe it will be different in the future," he said.
Berger also said that spectator and TV numbers are low for Formula E, which is not the case in DTM.