The phrase "assigned to the role of" is correct and usable in written English.
It can be used when describing someone's designation or position within an organization or project.
Example: "After a thorough evaluation, she was assigned to the role of project manager for the upcoming initiative."
Alternatives: "designated as" or "appointed to the position of".
Subjects were randomly assigned to the role of dictator or recipient.
But little value has been assigned to the role of native peoples in sustaining the Amazon.
Students are often assigned to the role of observer during simulation experiences.
In a second study, one group was assigned to the role of manager, another to the role of subordinate.
Participants were randomly assigned to imagine this scenario from the perspective of either the "target" or the "suitor". Similar to our first study, participants assigned to the role of "target" reported that they would feel more bad and uncomfortable rejecting their co-worker's advance than those assigned to the role of "suitor" imagined.
We manipulated both motivation and memory in a 2 × 2 between-subjects design, yielding four separate conditions where participants were assigned to the role of either buyer or seller, and had to rely more or less on memory.
Then, students are assigned to the roles of prosecutor and defense lawyer.
The two agents, assigned to the roles of unexceptional married suburbanites, unexpectedly fell in love, and they also care deeply about their children.
College student participants were randomly assigned to the roles of prison guard or prisoner and, in relatively short time, began exhibiting sadistic behavior or mental breakdowns.
Before the beginning of the experiment, the three different stimulus pairs were assigned to the roles of AB, CD and EF in a counterbalanced fashion, yielding six counterbalancing types (see Table 1).
They needed to be reminded on the day where the world celebrates the birth of a child whom Rome and Herod try to assign to the role of 'surplus population,' that the frightened men who rule the world in the name of scarcity should not be followed, but saved.
