It can be dangerous to put significant stock in first impressions when glancing at the initial submission of an assignment or lab report. Because I have just spent time presenting the material in the clearest way I know, I think it must be just as clear to the students as it is to me. Otherwise, they would have asked the relevant questions necessary to make it clear. As a result, I have high expectations for their performance on the assignment and quickly glance over the submissions as they come in. The results (performances) that correctly understood the concept do not create any cognitive dissonance because that was what was expected and focus on them is transitional and quickly shifts. First impressions instead focus on those who did not understand the concept and relative time spent on the two groups dose not match up exactly with the population size of both groups. As a result, I tend to over-estimate the number of students struggling and create a much more dire situation than the results actually call for.
Take home lesson – Don’t look at the assignments before I am actually ready to sit down, with some sort of rubric, and grade them. Also, don’t make a decision about student performance or assignment quality until looking at all the results of the whole class of students.
Chemistry with Dr. Mark 