On the other hand, something that does not offer any challenge at all is also not worth your time. If you practice a study technique and find that you are 100% accurate 100% of the time then you should start to get suspicious. You may need to increase the difficulty level, add in new material, or simply abandon the study technique all together. If you’re not getting anything wrong – ever – then you’re not learning! Of course, you might have a good day where you happen to do very well. Great! Celebrate the accomplishment and set the next goal. However, if there’s very little challenge then that’s a sign that the technique you’re using is either not effective or not appropriate for the material you are trying to learn.
There are several names for this phenomena in education and cognitive psychology (the “zone of proximal development” and “desirable difficulties” both describe a similar concept) but I like to think of this as the 3 Bears approach to learning. It shouldn’t be too hard or too easy, but somewhere in the middle that’s just right.
Note that what is too easy or too hard can and should change as you learn more! You will need to periodically reevaluate what is and is not working for you.
An important question to ask when determining whether or not a strategy has been working is: what does success look like? Depending on the nature of what you’re studying success can look very different. For terms and definitions it can be fairly straightforward: the proper terms and definitions come to mind much more quickly and easily. You might score higher on a practice quiz or game or complete a timed run more quickly. Other learning tasks may not be as straightforward. Improving your understanding and analysis of a text for a literature class may involve some more nuanced feedback from your instructor to know if your study strategy has been working. Practicing a creative skill like drawing or acting might also require some practice or skill to even be able to evaluate what improvements you have made.
Often what success looks like depends on how you will be assessed or how you expect your newfound knowledge will be used. A common type of assessment is a unit exam or an end of term cumulative test. In some subjects the assessment may be more hands on like a lab practical or a final performance. At the end of these assessments (whether they are given by an instructor or they are simply a goal you have set for yourself) you will have some kind of information about whether you have learned something or achieved your goal. However, the way you should prepare for each of these can be very different. You would not prepare for a clarinet recital by only making flashcards of the musical scale. That might be beneficial at first, if you have no previous knowledge of how to read sheet music, but you would expect to move on to actually playing the clarinet and producing the appropriate sounds. Maybe eventually you will produce something that someone else would call music. Similarly, if you have a final lab practicum in a science class then practice recalling terms and definitions might be useful at first, but you will need to move on to actually practicing the laboratory techniques that you will be tested on.
Generally, the more your practice/study technique/app/game looks like your final assessment or goal, the more beneficial it will be. As noted above, you may need to work up to that format depending on your level of background knowledge and experience, but as the quiz/test/recital/practicum approaches you should be doing something that resembles your goal. Be wary of any study technique that looks radically different or unrelated to how you will be assessed. Sometimes it might be a necessary step on the road towards your learning goal, and sometimes it can be a distraction from your goal. The only way to really know is to reevaluate periodically and, when possible, ask for feedback from your instructor.
References
(1) Kornell, N., & Bjork, R. A. (2007). The promise and perils of self-regulated study. Psychonomic Bulletin & Review, 14, 219-224.
(2) Karpicke, J. D., Butler, A. C., & Roediger, H. L. (2009). Metacognitive strategies in student learning: Do students practise retrieval when they study on their own? Memory, 17, 471-479.
(3) Hartwig, M. K., & Dunlosky, J. (2012). Study strategies of college students: Are self-testing and scheduling related to achievement? Psychonomic Bulletin & Review, 19, 126-134.