This was a qualification which the ATAA offered to its members. Ti earn it they needed to pass the two subjects that made up the ATAA Dip Ta, E114 Technical Analysis and E171 Specialised Techniques in Technical Analysis, which were offered through the SIA, later FINSIA. When FINSIA sold their education business to Kaplan, the arrangement ceased. The ATAA say they are developing an alternative, but there is nothing announced so far.
In the two subjects, I tried to bring together the basics of technical analysis from lots of sources. As the writer of E114 and much of E171, it is probably not for me to say how good they are.
In the subjects, I tried to give the whole discipline some structure, so that students can see where the various techniques fit together. I find students telling me that after doing the two subjects they have an excellent understanding of the subject.
The material in the course notes for E114 is available on my paid website under Technical Analysis Articles. There is also a mini course on candlesticks analysis, which was part of E171.