ISACA has stopped disclosing the CISA exam pass rate in recent years, but based on this presentation from University of Virginia and the linkedin conversation, you can expect a passing rate around 50% every year.
Whether a 50% pass rate is considered high or low is subject to interpretation.
First of all, there is no educational requirement to sit for the CISA exam. In other words, anyone can give it a try and this often attracts “casual takers” with no background in IT auditing. This naturally drags down the pass rate.
When compared to other accounting certifications, the CIA exam requires a bachelor degree to get qualified. The rules for CPA exam is even more stringent as state boards look for 150 credit hours (equivalent to 5 years of higher education), together with minimum accounting and business courses.
Therefore, the 50% pass rate in the CPA exam is very different from the 50% CISA exam pass rate. We can safely assume that the likelihood of passing the CISA exam is considerably higher than 50% if you have background knowledge in information system assets, the risks involved, controls implemented and the audit procedures
I am the author of How to Pass The CPA Exam (published by Wiley) and the publisher of this and several accounting professional exam prep sites.