Training programs, in industry, are a common way to increase awareness and change the behavior of individuals. The most popular way to determine the effectiveness of the training on learning outcomes is to administer assessments with Multiple Choice Questions (MCQ) to the participants, despite the fact that in this type of assessment it is difficult to separate true learning from guessing. This study specifically aims to quantify the effect of the inclusion of the 'I don't know' (IDK) option on learning outcomes in a pre-/post-test assessment construct by introducing a 'Control Question' (CQ). The analysis was performed on training conducted for 1,474 participants. Results show a statistically significant reduction in the usage of the IDK option in the post-test assessment as compared to the pre-test assessment for all questions including the Control Question. This illustrates that participants are learning concepts taught in the training sessions but are also prone to guess more in the post-test assessment as compared to the pre-test assessment.