Issue estoppel, while permitting relaxation of the strict requirements of res iudicata (same parties, same cause of action, same relief), must be applied on a case-by-case basis with careful scrutiny of considerations of equity and fairness. Deviation from the threefold requirements of res iudicata should not be allowed where it is likely to give rise to potentially unfair consequences in subsequent proceedings, consistent with the constitutional guarantee of a fair hearing in section 34. Where findings of fraud or other disputed facts were made inappropriately in motion proceedings without proper investigation and without the benefit of oral evidence, cross-examination and discovery, it would be inequitable and unfair to hold a party bound to those findings through issue estoppel in subsequent proceedings, as this would deprive them of the opportunity to properly test the allegations and have the findings reconsidered on appeal.