Screen test auditions are usually defined by the fact that the participant in Louisville gets a piece of paper and he/she is then asked to learn a short excerpt of the scripts. There you may be actually called again to showcase the same thing again in front of an Audition panel or officials. This is mostly the case in the auditions done in the Television and Film industry. Sometimes the participant is asked to send a video containing their dialogue from that script excerpt into the jury so to speak and then they will watch that video footage to determine whether the candidate looks good or bad on camera and exudes what they are looking for, for that character.
Though you should know that screen tests are not always held before casting large roles in Louisville and they are never used for smaller roles. Now that pretty much all auditions are digitally taped by casting directors, a “screen test” is often redundant, because literally every step of the audition has been a screen test at that point. But they can be useful when it’s impossible for all the decision makers to be in the casting room in Louisville.