Thanks for all the help. I conducted my first ever Moodle exam last week. I loved the ease of it, and most students liked the fact that graded answers and solutions were available soon after the exam was over.
However, this was an exam in engineering, and it revealed (perhaps due to my own lack of familiarity, or due to limitations in Moodle) a grave problem.
In engineering and in sciences, getting the right answer to a numerical problem is important, but perhaps even more important is the process employed in arriving at that right answer. So, in almost all cases, when the numerical answer is off, but the steps are right, the student should expect to get nearly full credit. Multiple choices questions do not test the kind of problem solving skills we are interested in testing. A pure multiple choice question exam is out of the question. Further, manual graded questions require a) a lot of student time as many of them are not yet fully comfortable with LaTeX, and b) kills one of the main attractions for instructors of large classes.
I had set about 3 problems (calculated type) with wildcards that made sure that no two students got the same numerical problem to solve. Further I had shuffle set, so that students would be unlikely to be on the same problem as their neighbors.
Now, this works as advertised, but the downside, which had been foreseen earlier, was that there was no possibility of partial credit.
In reality, several students ended up making silly numerical errors that do not reflect on their understanding of the subject, and I have had to do regrades with an ill-defined set of criteria.
This is not a desirable situation. Before I can recommend Moodle as a testing platform widely to my colleagues, I need to find a way to allow students to add an ungraded text field (like the essay question type) that is a part of a calculated type question, in which they show the rough working/steps for their answer. That would make regrading a lot less arbitrary, and even give instructors the option of considering such fields prior to releasing grades.
Cloze, regrettably is not the solution, as it does not seemingly support calculated type questions as sub parts with wildcards etc.
Any ideas would be welcome.