<p>Units of credit are not always a reliable way of comparing course workload.</p>
<p>4 unit science or engineering courses with labs tend to be much more work than 4 unit math or math-like courses (e.g. economics, computer science theory, engineering courses without labs). Lots of computer programming or large term projects (which can exist in humanities and social studies courses) also tends to make a course more work than its units may indicate.</p>