Saying you taught it but the student didn't learn it is like saying you sold it but the customer didn't buy it.
Alfie KohnWhat is wrong with encouraging students to put "how well they're doing" ahead of "what they're doing." An impressive and growing body of research suggests that this emphasis (1) undermines students' interest in learning, (2) makes failure seem overwhelming, (3) leads students to avoid challenging themselves, (4) reduces the quality of learning, and (5) invites students to think about how smart they are instead of how hard they tried.
Alfie KohnWe can't value only what is easy to measure; measurable outcomes may be the least important results of learning.
Alfie KohnNon-cooperative approaches, by contrast, almost always involve duplication of effort, since someone working independently must spend time and skills on problems that already have been encountered and overcome by someone else. A technical hitch, for example, is more likely to be solved quickly and imaginatively if scientists (including scientists from different countries) pool their talents rather than compete against one another.
Alfie Kohn