Is the difference what a PADI instructor can require as opposed to what they can add? For example, can a PADI instructor require 12 completed dives for OW certification or a score of 100% on the OW written test? Can they require a vertical CESA?
I can't answer for PADI, but would like to just say that I believe adding skills or requiring additional dives needs to make sense ... in other words, regardless of whether the agency allows it or not it should only be done if it adds some sensible value to the learning experience. Some examples ...
- Mask clear ... is it sufficient to just see it done? What if the student appears apprehensive, or on the verge of panic when they flood the mask? Is it in their best interest to pass them when they can barely perform the skill in the "baseline" condition of being stationary, with an instructor facing them, at a time when they're clearly expecting to have to perform the skill? How well will they deal with a situation later on if they're swimming and their mask is accidentally kicked? Will it trigger a panic or near-panic response? How "safe" is that? I won't pass a student on this skill until they demonstrate to me that they can clear their mask easily, comfortably, and without undue stress or apprehension. The standards don't specify those conditions ... I do it because it creates a safer, more confident diver.
- Number of dives ... I've been known to add dives to the curriculum, particularly for the repetition of skills that I feel the student needs to work on before becoming certified. Given the conditions I teach in, this isn't uncommon ... there's a significant difference between pool conditions and Puget Sound, and sometimes it takes more than the requisite five dives to acquire the comfort and competence to perform the same skills during checkout dives that the student "mastered" in the pool. Given the addition of gloves, hood, heavy wetsuit or drysuit, and the requisite weight to sink all that exposure protection ... and adding in the discomfort of low vis conditions that are common here ... a couple extra dives is often a good idea to give the student practice and confidence before turning them loose to plan and execute their own dives ... particularly since we don't do guided dives here, and students come out of OW with the expectation that they'll be able to dive unsupervised.
- Test score ... NAUI requires a minimum passing grade of 70%. Bob requires a minimum passing grade of 80%. If the students can't manage that score, it's an indication that I haven't done an adequate job of explaining the material ... and we'll keep going until the student comprehends not only what they're supposed to have learned, but why it's important. In the almost nine years that I've been teaching, I can count on one hand the number of students who haven't been able to achieve 80% or better on the first attempt. Also, with respect to test scores, there are a few questions on all of the exams for the courses I teach that I consider unimportant. I really don't care if the student knows which law is Henry's and which is Boyle's ... I care that they understand that those laws are meant to convey, and how it applies to what they'll be doing. If they get the concept right, but get the names confused, I do not consider it a wrong answer.
These are just a few examples of standards deviations that I feel are sensible, serve the best interests of the student, and generally produce divers who are more competent, confident, and far more likely to continue diving once they're certified. A couple years back I went through my student records and could verify that nearly 80% of those I've taught since 2004 are still actively diving ... quite a few of them still dive with me from time to time, in fact ...
... Bob (Grateful Diver)