Hi Chillie123,
Judicial review does not look at the merits of the case. This is due to the separation of powers. Judicial review is an administrative/executive function. the reason why judicial review cannot (or rather, should not) consider the merits of a case is to maintain certainty and finality of judgments. Further, those exercising judicial review are only asking whether the judge had power or was correct in deciding upon the case. It is not meant to "judge the Judge" so to speak. Judges are considered competent enough to make their own decisions on merits and another judge should not be questioning them except for in limited situations (judicial/procedural review or appeals on questions of law).
Judicial review looks at issues such as:
- Did the decision maker have power to decide in this case?
- If so, did the decision maker act according to their powers (what was giving to them under legislation) or did they act outside of these powers?
- Did the decision maker follow correct procedure?
It does not ask questions such as did they apply the proper facts to the law, evidentiary matters, did they follow proper procedure and rules, should they have ruled this way rather than that way, were they correct in accepting one version of facts over another etc.
In practice, the line between the two may get murky since sometimes it is not possible to ask "did they act outside of power in making their decision" without turning to the substance of the dispute and what factors the decision maker considered and how much they impacted the ultimate decision. However, most administrative reviews are done by experienced people who are good at balancing this line.
To give a blunt analogy (off the top of my head), review of merits is like going in and judging a parent for how they parent/teach their child and then substituting their parenting decisions with one of out own because we think it is better/correct. Judicial review, on the other hand, is like asking, is that person really a parent of that child so that they are able to making parenting/guardianship decisions for the child? If not, we cannot allow that parenting decision to stand. But if yes, we should not intervene (except in limited circumstances) and substitute their decision for our own.