Sufficiency of Reasons
The accused may appeal from a verdict on the basis that that reasons of the Court were insufficient. The sufficiency of reasons is not a "standalone" ground of appeal. Rather it is a component to a ground of appeal for "reasonable verdict" under s. 686(1)(a)(i) or for a "miscarriage of justice" under s. 686(1)(a)(iii).
Purpose of Reasons
The goal of giving reasons is to "show why the judge reached his or her conclusion".
There is also the legal presumption that judges know the law and apply it correctly. The need for reasons is balanced against the danger of "slow[ing] the system of justice immeasurably." Judges give oral reasons on a daily basis, frequently limiting their reasons to the essential points. A reviewing court cannot "require them to explain in detail the process they followed to reach a verdict."
Generally, reasons are needed to address any confused or contradictory evidence on an important issue.
The burden is upon the appellant to show that the judge gave insufficient reasons.
Standard of Proving Insufficiency
The standard of review with respect to the insufficiency of reasons is on the standard of "adequacy". The reasons will be adequate " if, when read in their entire context, they fulfill the threefold purpose of informing the parties of the basis of the verdict, providing public accountability and permitting meaningful appeal."
The judge must only demonstrate "he came to grips with the issues thus defined by the defence".
To form a valid ground of appeal the appellant must show that 1) the reasons were insufficient and 2) that the deficiency created "prejudice to the exercise of his or her legal right to an appeal in a criminal case"
No Need to be Comprehensive
The judge is not required to "answer every argument, reconcile every frailty in the evidence, refer to all the conflicting evidence, and set out every finding made in reaching a verdict".
There is no need to reference in the written judgement every item of evidence that was adduced.
Just because the judge failed to address every consideration they made does not mean they failed to consider other reasons or did not exercise discretion judiciously.
see R v 2002 SCC 26 (CanLII),  1 SCR 869 per Binnie J
R v Wigle, 2009 ONCA 604 (CanLII)
- Sheppard, supra
R v JR, 2014 QCCA 869 (CanLII), at para 26 per Hesler CJQ
R v Burns, 1994 CanLII 127 (SCC) per McLachlin J
- Burns, ibid.
R v Boucher, 2005 SCC 72 (CanLII) per Deschamps J
R v DR, 1996 CanLII 207 (SCC),  2 S.C.R 291, para 55 per Major J
Sheppard, supra para 54
JR, supra at para 26
R v Oddleifson, 2010 MBCA 44 (CanLII) at para 30 per Chartier JA
Ali, supra at para 14
Sheppard, supra, at para 25
R v Sheppard, supra at para 33 (“not only that there is a deficiency in the reasons, but that this deficiency has occasioned prejudice to the exercise of his or her legal right to an appeal in a criminal case”)
R v Ali, 2015 BCCA 333 (CanLII), at para 13 per Stromberg-Stein JA
R v M. E-H., 2015 BCCA 54 (CanLII) at para 68 per MacKenzie JA
R v Tse, 2013 BCCA 121 (CanLII) at para 56
R v Blacklaws, 2012 BCCA 2017(?) aff'd at 2013 SCC 121 (CanLII)
R v Dinardo, supra at para 30
R v Cote, 2016 ABCA 387 (CanLII) at para 13
R v Anderson, 2013 ABCA 160 (CanLII) at para 13
R v Beals, 1993 CanLII 5636 (NS CA),  NSJ No 436 at paras 16 and 29
Reasons for judgement will be sufficient where the reasons "read in context, show why the judge decided as he did" on the appropriate counts.
The judge is required to give reasons for his or her decision on verdict.
A judgement is sufficient if when "read in context, show why the judge decided as he or she did".
Appellate review must take a "functional approach".
In a case that turns on determination of credibility, the reasons should be "considered in light of the deference afforded to trial judges on credibility findings". Intervention on this basis for credibility cases should be "rare". Absent a "palpable and overriding error by the trial judge" the perception of the judge should be respected.
There is no obligation upon judges to address every argument made by counsel.  Nor must the judge articulate consideration of every part of the evidence.
The Criminal Code specifically mandates judges to give reasons on certain circumstances, such as when determining the admissibility of a complainant's prior sexual history ; ordering the production of prior personal information (s. 278.8(1)); and when imposing a sentence .
The reason must "sufficiently intelligible" to permit appellate review.
A verdict must be based exclusively on admissible evidence heard at trial. If a trial judge has misapprehended the evidence, including resorting to material not before him or her, and the errors "play an essential part in the reasoning process resulting in a conviction then … the accused’s conviction is not based exclusively on the evidence and is not a “true” verdict". 
On findings concerning credibility focus on analysis "should be directed at whether the reasons respond to the case's live issues, having regard to the evidence as a whole and the submissions of counsel" This however does not require "reasons to be so detailed that they allow an appeal court to retry the entire case on appeal. There is no need to prove that the trial judge was alive to and considered all of the evidence, or answer each and every argument of counsel." Credibility cases require that the court sufficiently articulate how credibility concerns have been resolved. Failure to do so may be a reversible error.
Credibility assessments should be accorded a high degree of deference.
R v Vuradin, 2013 SCC 38 (CanLII), per Karakatsanis J, at para 15
R v Sheppard,  SCJ No 30, 2002 SCC 26 (CanLII), per Binnie J, at para 55
Pitts v Ontario, 1985 CanLII 2053 (ON SC), (1985), 51 OR (2d) 302, per Reid J, at p. 311
R v Kendall, 2005 CanLII 21349 (ON CA),  O.J. No. 2457 (C.A.), per Cronk JA
Vuradin, supra at para 12
R v REM, 2008 SCC 51 (CanLII),  3 SCR 3, per McLachlin CJ, at para 17
R v AA,  O.J. No. 4016 at para 116
Vuradin, supra at para 10
R v Dinardo, 2008 SCC 24 (CanLII), per Charron J, at para 26
Dinardo, ibid. at para 26
R v Gagnon, 2006 SCC 17 (CanLII), per Bastarache and Abella JJ, at para 20
- Dinardo, supra at para 30
- see s. 276.2(3)
- see s. 726.2
- R v JJRD, 2006 CanLII 40088 (ON CA), (2006), 215 CCC (3d) 252 (Ont. C.A.), at para 35 per Doherty JA
R v Morrissey, 1995 CanLII 3498 (ON CA) at p. 541 per Doherty JA
R v Lohrer, 2004 SCC 80 (CanLII),  3 SCR 732, at paras 2-3 per Binnie J
- Dinardo, supra, at para 25
Dinardo, supra at para 30
also referenced in REM, supra
Dinardo, supra at para 26
R v Braich, 2002 SCC 27 (CanLII),  1 SCR 903, at para 23 per Binnie J
R. v. A.A.  O.J. No. 4016 at para 116
Where the judge or jury provides verdicts that are "irreconcilable such that no reasonable jury, properly instructed, could possibly have rendered them on the evidence" then the verdict is unreasonable.
- R v Pittman, 2006 SCC 9 (CanLII) at para 10
Timing of Reasons
Reasons for decision may not be valid where the delay between the ruling and the release of reasons are such that "a reasonable person could not be satisfied that the reasons for judgment actually reflect the reasoning process that led to the decision".
All reasons released "are presumed to reflect the reasoning that led him [the trial judge] to his decision". The presumption is rebuttable by factors including the passage of time which causes "a reasonable person would apprehend that the written reasons are, in effect, an after-the-fact justification for the verdicts rather than an articulation of the reasoning that led to the decision".
Standard of Review
The reasons are to be examined in a functional test. "The requirement of reasons is tied to their purpose and the purpose varies with the context" The functional and substantive manner means taking the reasons, "as a whole, in the context of the evidence, arguments, and the live issues at trial, with an appreciation of the purposes or functions for which reasons are given. There must be a logical connection between the verdict and the reasons. 
The purpose of the reviewing court is to "isolate those situations where deficiencies in the trial reasons will justify appellate intervention and either an acquittal or a new trial".
When considering sufficiency, it is not the decision alone that should be considered but rather "what the trial judge has stated in the context of the record, the issues and the submissions of counsel at trial".
Where an oral and written decision contains inconsistent findings and reasons to key findings, a new trial may be warranted.
- informing the parties of the basis of the verdict,
- providing public accountability and
- permitting a form of appeal.
Failure to evaluate a complainant's evidence in light of independent contradictory evidence is a reverseable error.
Inadequate reasons alone does not warrant appeal unless the deficiency creates a "prejudice to the exercise of his or her legal right to an appeal in a criminal case."
There are three categories of cases where prejudice is caused by deficient reasons:
- Allegation of unreasonable verdict cases;
- Allegation of error of law cases; and
- Miscarriage of justice cases.
Insufficient reasons are an error of law when they prevent any meaningful appellate review. 
- R v Sheppard, 2002 SCC 26 (CanLII),  1 SCR 869
- Dinardo, 2008 SCC 24 (CanLII),  1 SCR 788 at para 24
R v TS, 2012 ONCA 289 (CanLII) at para 45
R v REM 2008 SCC 51 (CanLII) at paras 16, 35, 55
- Sheppard, supra at para 21
- REM, supra at para 37
- R v Ball 2012 ABCA 184 (CanLII)
- R v Flores, 2013 MBCA 4 (CanLII)
See also R v Oddleifson (J.N.), 2010 MBCA 44 (CanLII)
- R v Hanson (K.J.), 2010 ABQB 128 (CanLII)
- Sheppard, supra at para 33 ("A more contextual approach is required. The appellant must show not only that there is a deficiency in the reasons, but that this deficiency has occasioned prejudice to the exercise of his or her legal right to an appeal in a criminal case.")
- Sheppard, supra
- R v Sheppard, 2002 SCC 26 (CanLII)