rationale

/ˌræʃəˈnɑːl ˌरैशˈनाल्‌/ noun [C] ( formal )

the rationale (behind/for/of something) the principles or reasons which explain a particular decision, course of action, belief, etc. विशिष्‍ट निर्णय, कार्रवाई, धारणा आदि के आधारवर्ती सिद्घांत या तर्क

What is the rationale behind these new exams?