During the extended essay, I had to choose whether I should continue working with the experiment that just did not work. I have realised that the rate of this reaction I was investigating was so low that there is no possibility to investigate this reaction in a laboratory. At that moment I remembered the book on organic chemistry (V. F. Traven, 2004) where I read about the reaction of racemization of glucose and immediately picked this option.
Another example of a crucial decision making happened to me when I realised that I can add some more data points to those that already exist. So in my investigation, I chose to heat glucose solutions not only for 10 minutes but also 20 minutes which definitely added a lot of certainty to my results.