Canadian Criminal Procedure and Practice/Appeals/Standard of Review
All reviewable decisions made by a judge can be seen as answering one of three categories of questions:
- questions of law: what is the correct legal test to be applied
- questions of fact: what took place between the parties
- questions of mixed law and fact: whether the facts satisfy the correct legal tests
All questions of law are to be reviewed on a standard of "correctness". All questions of fact are reviewed on a standard of "palpable and overriding error".
All findings of facts are questions of fact.
A question of law inquire into the "correct legal test" to be applied for a particular legal issue or "the application of a legal standard" to facts. This also includes the interpretation of a legal standard and the application of a standard to settled facts. However, where the facts are in dispute, it is most likely a question of mixed fact and law.
Where the question is neither purely a question of law or question of fact, then it is considered a question of ""questions of mixed law and fact".
- Housen v. Nikolaisen,  2 S.C.R. 235 at paras. 8, 10, 11, 12, 26, 31, 39, 72, and 101
- see also Saint-Jean v. Mercier,  1 S.C.R. 491
Housen v. Nikolaisen ,  2 S.C.R. 235 at para. 8
R. v. Mooney, 2005 NLCA 49 at para. 18
- R. v. Shepherd, 2009 SCC 35
Pushpanathan v. Canada (Minister of Citizenship and Immigration) ,  1 S.C.R. 982 at para. 37
Saint-Jean v. Mercier,  1 S.C.R. 491 at para. 33
R. v. Araujo ,  2 S.C.R. 992 at para. 18
R. v. Shepherd, 2009 SCC 35
R. v. Brooks, 2000 SCC 11
- R. v. Ewanchuk ,  1 S.C.R. 330 at para. 21
- R. v. Mara,  2 S.C.R. 630 at paras. 18-19
- R. v. Grouse 2004 NSCA 108 at para. 44
Questions of LawEdit
The admissibility of photos is reviewed on the standard of correctness.
The issue of the exclusion of evidence under s.24(2) is a matter of law, however, one with “considerable deference”. 
Reviewing a judge’s decision a whether there was a Charter breach is determined on the standard of correctness. However, the evidence underlying the Charter matter can only be reviewed on the standard of “palpable and overriding error”.
The issue of whether the facts amount to "reasonable and probable grounds" is a question of law.
Errors in law require the appellant to establish not only an error but that "the error (or errors) of the trial judge might reasonably be thought, in the concrete reality of the case at hand, to have had a material bearing on the acquittal". But does not need to go so far as to convince the court that "the verdict would necessarily have been different" 
A Crown appeal of an acquittal, errors in law include:
- making a finding of fact for which there was no evidence;
- where the legal effect of findings of fact or undisputed fact raises a question of law;
- an assessment of the evidence based on a wrong legal principle; and
- a failure to consider all of the evidence in relation to the ultimate issue of guilt or innocence.
The following have been found to be questions of law and so reviewable on the standard of correctness:
- Admissibility of Evidence
- Failure to consider admitted evidence;
- the relevance of evidence;
- Interpretation of a section of the Criminal Code;
- the interpretation of a "legal standard" 
- Whether someone was unlawfully detained under s. 9 of the Charter;
- whether an utterance is a "threat to cause bodily harm"
- whether the judge correctly put a defence to a jury;
- whether there is an air of reality to a defence;
- a directed verdict
- misdirection of a jury (not including non-direction of a jury)
- A dissenting court of appeal judge on the issue of unreasonable verdict
- whether corroboration is needed to establish a fact.
- admission of inadmissible evidence through improper cross-examination questions
- the reasonableness of grounds, such as in forming grounds of detention
- R v Blea, 2012 ABCA 41,  AJ No 106 at para 31
- see R. v. Grant at para. 86, and R. v. Beaulieu, 2010 SCC 7 at para. 5
- R v Farrah 2011 MBCA 49 at 7
- R. v. Shepherd 2009 SCC 35, 309 D.L.R. (4th) 139 at para. 18, 20 ("[w]hile there can be no doubt that the existence of reasonable and probable grounds is grounded in the 'factual findings' of the trial judge, the issue of whether the facts as found by the trial judge amount at law to reasonable and probable grounds is a question of law")
see R. v. Graveline, 2006 SCC 16,  1 S.C.R. 609 at para. 14
R. v. Duguay, 2007 NBCA 65 at paras. 26-27
- see R. v. J.M.H., 2011 SCC 45 at 24-32
- R. v. Simpson (1977), 35 C.C.C. (2d) 337 (Ont. C.A.)
R. v. Starr,  2 S.C.R. 144, 2000 SCC 40, at para. 184;
R. v. Harper,  1 S.C.R. 2
- R v Mohan, 1994 CanLII 80 (SCC),  2 SCR 9 at 20
- R. v. Mohan,  2 S.C.R. 9 at para. 18
R. v. Goulet, 2011 ABCA 230 at para. 7
R. v. McColl, 2008 ABCA 287 at para. 8
R. v. Araujo,  2 S.C.R. 992 at para. 18
- R v Shepherd, 2009 SCC 35 (CanLII), 2009 SCC 35,  2 SCR 527 at para 20
- R. v. Felteau 2010 ONCA 821
- R v Tran, 2010 SCC 58 at 40
- R. v. Cinous (2002), 162 C.C.C. (3d) 129 at para. 55
- R. v. Barros (2011), 273 C.C.C. (3d) 129 (S.C.C.), at para. 48
- R. v. Luciano 2011 ONCA 89 at para. 70
R. v. Yebes,  2 S.C.R. 168
R. v. Biniaris,  1 S.C.R. 381
R v Hubin,  S.C.R. 442
R v Steele (1924), 42 C.C.C. 375 (SCC)
- R. v. Mian 2012 ABCA 302 (CanLII)
- R. v. Moore, 2012 BCCA 400 (CanLII)
Questions of FactEdit
Where a palpable and overriding error has been found, the judge may intervene with its view of the evidence as well as draw inferences based on that evidence.
The following have been found to be questions of fact and so reviewable on the palpable and overriding error:
A judge's assessment of evidence, such as whether a judge can rely on a document for the truth of its contents, is reviewed on a standard of palpable and overriding error that the finding of fact played an essential part in the reasoning.