The social studies teacher allows her students to use an old encyclopedia during essay tests, because she believes this builds critical-thinking skills in her students.
The social studies teacher allows for her students' use of an old encyclopedia during essay tests, because she believes this builds critical-thinking skills in her students.
The social studies teacher allows her students to use an old encyclopedia during essay tests, because she believes this builds critical-thinking skills in her students.
The social studies teacher allows for her students' use of an old encyclopedia during essay tests, because she believes this builds critical-thinking skills in her students.
The correct idiom for simple permission is "allow A to do X" (one person gives another person conscious permission for something). The idiom "allow for" might be used to mean "to make allowances for" (in the design of a mechanical process or for an unintended consequence), which is not appropriate here.