Limitations are flaws or deficiencies that may have influenced your outcomes. If anything tough about your study was challenging but had no effect on the outcomes, it was most likely a challenge rather than a constraint. As a result, difficulties should not be discussed in your discussion chapter. Issues are problems or mistakes that may have affected your results. For example, if you performed a study with human subjects and did not obtain informed consent, this would be an issue that could potentially affect how we think about your study's findings. Challenges are things that might have made doing the study difficult or impossible; for example, if you were studying brain activity and needed to use MRI machines, that would be a challenge. Limitations and issues should both be listed in your discussion chapter. However, limitations usually involve problems with design or methods used in your study while issues tend to concern actual events during the course of your study. For example, if participants in your study gave inconsistent answers to questions, this would be an issue with the data obtained from those participants. It is important to distinguish limitations from issues because they carry different implications for future studies. Issues can sometimes be resolved by simply repeating the study (for example, if getting consistent results was a problem, then further studies could include more rigorous methods). On the other hand, limitations cannot be fixed by simply repeating the study process so they require additional analysis or discussions with other researchers.