Building and maintaining exams with dynamic content

Part of my job as a researcher and teacher is to periodically apply and grade exams in my classroom. Being constantly in the shoes of an examiner, you soon quickly realize that students are clever in finding ways to do well in an exam without effort. These days, photos and pdf versions of past exams and exercises are shared online in facebook, whatsapp groups, instagram and what not. As weird as it may sound, the distribution of information in the digital era creates a problem for examiners. If you use the same exam from past year, it is likely that students will simply memorize the answers from a digital record.