The table uses a numeric grading system to compare the result produced by the built-in integrate function provided by each system with the optimal antiderivative as shown in the above file. Simplification of results using functions and/or domain restrictions on variables is not allowed. In other words, the results a novice user would see are graded as is.
For each problem, if the system gives a result as good as the optimal antiderivative, 2 points are earned. If the system gives a mathematically correct result (i.e. its derivative equals the integrand) but is substantially more complex than the optimal antiderivative (e.g. significantly larger or involves the imaginary unit), 1 point is earned. If the system is unable to integrate the expression in closed-form or times-out after 30 seconds or so, no points are earned. If the system returns a mathematically incorrect result, 1 point is decremented. So a perfect score on the Charlwood Fifty test-suite is 100.
I would be happy to include other systems in the table if a knowledgeable user sends me its version number and numeric grades and/or raw test results for each of the 50 problems using the scoring system described above. Also if you think I have unfairly graded a system, please provide evidence and I will revise the table accordingly.
Of course, the improvement of Rubi from a score of 65 to 85 was due to version 4.1 having been written in light of the Charlwood Fifty test-suite. Hopefully the other systems will quickly improve their scores as well...