Qualified Expert Evidence: Difference between revisions

Latest revision as of 07:05, 23 July 2024

This page was last substantively updated or reviewed July 2021. (Rev. # 95699)

< Evidence
< Opinion Evidence

General Principles

Expert opinion is testimonial evidence that gives an opinion on facts perceived by him or another that concerns an issue that is likely outside the experience and knowledge of the trier-of-fact (i.e. a lay person). ^[1] The expert must have special knowledge in the matter ^[2] and the opinion must be reasonably necessary to assist the trier-of-fact to make a proper judgment. ^[3] There must also be no exclusionary rules that would otherwise prohibit the evidence from being given. ^[4]

The use of expert evidence in litigation is essential, especially in cases that involve "highly technical areas" that could not be litigated without assistance.^[5]

Burden of Proof

The presumption for any given witness is that an opinion evidence is not admissible.^[6]

Specialized Knowledge Vs Expert Opinion

A person testifying to specialized to technical knowledge will not necessarily be required to be qualified as an expert. Where they testify to their "factual knowledge" based on their "knowledge, observations and experience."^[7]

It has been accepted that technical evidence describing the "general rule and its exceptions" of the functioning of complex systems is not opinion evidence where the "understand[ing] the scientific and technical underpinnings" are not necessary to give reliable descriptions.^[8]

An expert who testifies to direct observation without opinion is not subject to the opinion rule of exclusion. This evidence is admitted in the same way as eye-witness evidence.^[9]

The expert is not to testify to facts, but rather only opinion to allow the trier-of-fact to draw inferences. ^[10]

Relevance

Relevance is "a threshold requirement" to admitting expert evidence.^[11]

Specialization

The key requirement for expert evidence is that the expert "possesses special knowledge and experience going beyond that of the trier of fact."^[12] As long as the court is satisfied that the witness is sufficiently experienced he should be qualified.^[13]

Any deficiencies of the knowledge or opinion simply goes to weight.^[14]

The means by which the skill, expertise, or knowledge was acquired goes to weight and not admissibility.^[15] It is acceptable to obtain the ability to give an opinion from study, instruction, practical experience or observations. Formal study in not necessary.^[16]

Specialization and Usurpation of the Court

Specialization brings with it a risk that the jury "will inappropriately defer to the expert’s opinion rather than carefully evaluate it."^[17] Courts must be wary of the "allure of scientific infallibility" that creates the risk of the evidence "swallow[ing] whole the fact-finding function of the court."^[18] Courts must be vigilent to draw a "firm line" between the role of the expert and the court..^[19] The closer the opinion is to the ultimate question for the court to determine the stricter limitations that must be placed on the evidence.^[20]

Jury Instruction

Where a qualified expert gives opinion evidence outside of their field, the problem can generally be remedied through a "remedial instruction advising the jury to disabuse their minds of the inadmissible evidence."^[21]

Standard of Review

Trial judges are entitled to "wide discretion" and deference when weighing the costs and benefits of admitting expert evidence.^[22]

Whether someone can be qualified as an expert is a question of law and is reviewable on a standard of correctness.^[23]

The admission of expert opinion is reviewable on the standard of correctness.^[24] However, absent error in principle, the reviewing court should be reluctant to interfere with the trial judge's decision.^[25]

↑ Folkes v Chadd (1782), 3 Dougl. 157
R v J-L J, 2000 SCC 51 (CanLII), [2000] 2 SCR 600, per Binnie J, at para 56
R v Abbey, 1982 CanLII 25 (SCC), [1982] 2 SCR 24, per Dickson J
R v Mohan, 1994 CanLII 80 (SCC), [1994] 2 SCR 9, per Sopinka J at 413 (the opinion must "provide information ‘which is likely to be outside the experience or knowledge of’” the trier of fact")
R v Bunniss, 1964 CanLII 673 (BC SC), (1964), 44 CR 262 (BC Co. Ct.), per Tyrwhitt-Drake J (an expert is "one who has by dint of training and practice, acquired a good knowledge of the science or art concerning which his opinion is sought, and the practical ability to use his judgment in that science")
↑ R v Terceira, 1998 CanLII 2174 (ON CA), 123 CCC 1 (Ont. CA), per Finlayson JA Mohan, supra, at p. 414 (the witness must be “shown to have acquired special or peculiar knowledge through study or experience in respect of the matters on which he or she undertakes to testify”)
↑ Mohan, supra
R v Lovie, 1995 CanLII 801 (ON CA), 100 CCC (3d) 68, per Finlayson JA
↑ R v NO, 2009 ABCA 75 (CanLII), 186 CRR (2d) 60, per curiam, at para 19
↑ Whitfield v. Whitfield, 2016 ONCA 581 (CanLII), 401 DLR (4th) 128, per curiam ("There is no question that expert evidence is essential to the litigation process and that many cases involving highly technical areas could not be tried without")
R v Abbey, 2009 ONCA 624 (CanLII), 246 CCC (3d) 301, per Doherty JA, at para 73, leave to appeal to SCC refused
↑ Abbott and Haliburton Company v WBLI Chartered Accountants, 2013 NSCA 66 (CanLII), 361 DLR (4th) 659, per MacDonald CJ (dissenting on other issue), at para 24
↑ R v Hamilton, 2011 ONCA 399 (CanLII), 271 CCC (3d) 208, per curiam, at paras 273 to 284 - evidence from phone company as to the mechanical workings of cell towers and their relationship to the cell phone
R v Ranger, 2010 ONCA 759 (CanLII), OJ No 4840, per curiam -- cell phone tower evidence
contra R v Korski, 2009 MBCA 37 (CanLII), 244 CCC (3d) 452, per Steel JA -- required expert to testify on cell tower evidence
R v Potter, 2020 NSCA 9 (CanLII), per curiam, at paras 441 to 423
R v Ajise, 2018 ONCA 494 (CanLII), 361 CCC (3d) 384, at para 23
R v MacDonald, 2020 NSCA 69 (CanLII), at para 58, per Derrick JA (“ Technical evidence grounded in experience, without more, does not constitute expert evidence.”)
↑ Hamilton, supra, at paras 273, 274, 277
↑ R v KA, 1999 CanLII 3793 (ON CA), 137 CCC (3d) 225, per Charron JA, at para 72
↑ R v Parrott, 2001 SCC 3 (CanLII), [2001] 1 SCR 178, per Binnie J
R v Lavallee, 1990 CanLII 95 (SCC), [1990] 1 SCR 852, per Wilson J
↑ Mohan, supra, at p. 411
↑ R v Béland, 1987 CanLII 27 (SCC), [1987] 2 SCR 398, per McIntyre J, at p. 415
R v Marquard, 1993 CanLII 37 (SCC), [1993] 4 SCR 223, per McLachlin J, at para 35
R v Chan, 1993 ABCA 383 (CanLII), 145 AR 304, per curiam, at para 9
↑ Chan, ibid., at para 9
↑ Chan, ibid., at para 9
↑ Chan, ibid., at para 9 citing Sopinka, Lederman and Bryant, The Law of Evidence of Canada (1992), at pp. 536‑537: ("As long as the court is satisfied that the witness is sufficiently experienced in the subject matter at issue, the court will not be concerned with whether his or her skill was derived from specific studies or by practical training, although that may affect the weight to be given to the evidence.")
R v Rayner, 2000 NSCA 143 (CanLII), 189 NSR (2d) 144, per Saunders JA
↑ R v Melaragni, 1992 CanLII 12764 (ONSC), 73 CCC (3d) 348, per Moldaver JA
R v NO, 2009 ABCA 75 (CanLII), 186 CRR (2d) 60, per curiam, at para 22
↑ Parliament v Conley, 2021 ONCA 261 (CanLII), 155 OR (3d) 161, per Harvison Young JA, at para 43
White Burgess Langille Inman v. Abbott and Haliburton Co, 2015 SCC 23 (CanLII), [2015] 2 SCR 182, at para 17
R v Mohan, 1994 CanLII 80 (SCC), [1994] 2 SCR 9, at pp. 21-22
↑ Whitfield, supra at para 47
Abbey, supra, at para. 71
↑ Whitfield, supra at para 47
J-LJ at para 25 to 26
↑ Whitfield, supra at para 47
J-LJ at para 37
↑ R v Sekhon, 2014 SCC 15 (CanLII), [2014] 1 SCR 272, per Moldaver J, at para 48
↑ R v Clark, 2016 ABCA 72 (CanLII), per curiam, at paras 59 to 62
R v DD, 2000 SCC 43 (CanLII), [2000] 2 SCR 275, per Major J, at para 13
R v Soni, 2016 ABCA 231 (CanLII), 339 CCC (3d) 294, per curiam (2:1), at para 8
R v Dominic, 2016 ABCA 114 (CanLII), 335 CCC (3d) 178, per curiam, at para 17
R v Abbey, 2009 ONCA 624 (CanLII), 246 CCC (3d) 301, per Doherty JA, at para 97, leave to appeal to SCC refused
↑ R v Bear (C.W.), 2013 MBCA 96 (CanLII), 299 Man R (2d) 175, per Steel JA, at para 81
↑ R v Grandinetti, 2003 ABCA 307 (CanLII), 178 CCC (3d) 449, per McFadyen JA, at paras 90{{{3}}} aff’d, R v 1jmfq, SCC 5 (CanLII) {{{3}}}
R v Leinen, 2013 ABCA 283 (CanLII), 301 CCC (3d) 1, at para 21
↑ R v Andres, 2003 ABCA 333 (CanLII), 112 CRR (2d) 117, per Fraser ACJ{AtL|dwc|21}}
R v B(CR), 1990 CanLII 142 (SCC), [1990] 1 SCR 717, per McLachlin J, at para 29
Leinen, supra, at para 21

Requirements of Expert Evidence ("Mohan" Test)

Legal Requirements for Qualified Expert Evidence

Procedure

Procedure for Calling Expert Evidence

Evidence

Rules of Evidence for a Qualified Expert

Example Fields of Qualifications

Established Fields of Expert Evidence

Opinion Evidence Outside of Qualification

Where a qualified expert testifies to matters directly outside of their area of qualification but is clearly within their area of special knowledge, the evidence can still be accepted, absent any objection to the evidence by the opposing side.^[1] Likewise, a technical failure to qualify someone who clearly has expertise in the area, absent any objections, should be permitted to give expert evidence.^[2]

↑ R v Marquard, 1993 CanLII 37 (SCC), [1993] 4 SCR 223, per McLachlin J, at pp. 242-44
↑ Marquard, ibid., at pp. 242-44

Where Technical Evidence Does Not Require Expert Evidence

There is some difference in opinion of whether or not expert qualification is needed to present evidence from cell phone towers.^[1] It is generally accepted that even where it is not necessary, it is useful to explain some of the records.^[2]

Evidence on the regular functioning of social media websites can in circumstances be accepted without qualification.^[3]

↑ R v Hamilton, 2011 ONCA 399 (CanLII), 271 CCC (3d) 208, per curiam, at paras 273 to 284 - evidence from phone company as to the mechanical workings of cell towers and their relationship to the cell phone. However, they did not give evidence triangulating the location of the accused's phone.
R v Ranger, 2010 ONCA 759 (CanLII), OJ No 4840, per curiam -- cell phone tower evidence accepted without qualification for general location evidence
cf. R v Korski, 2009 MBCA 37 (CanLII), 244 CCC (3d) 452, per Steel JA -- required expert to testify on cell tower evidence
↑ e.g. R v McBean, 2011 ONSC 3125 (CanLII), per Fuerst J
↑ R v Soh, 2014 NBQB 20 (CanLII), 1079 APR 328, per LaVigne J

@@ Line 1: / Line 1: @@
+[[Fr:Preuve_d%27expert_qualifiée]]
+{{Currency2|July|2021}}
 {{LevelZero}}{{HeaderOpinions}}
 ==General Principles==
@@ Line 5: / Line 7: @@
 <ref>
 ''Folkes v Chadd'' (1782), 3 Dougl. 157<br>
-''R v J-L J'', [2000] 2 SCR 600, [http://canlii.ca/t/5246 2000 SCC 51] (CanLII){{perSCC|Binnie J}}{{atL|5246|56}}<br>
+{{CanLIIRP|J-L J|5246|2000 SCC 51 (CanLII)|[2000] 2 SCR 600}}{{perSCC-H|Binnie J}}{{atL|5246|56}}<br>
-{{CanLIIR|Abbey|1lpcd|1982 CanLII 25 (CanLII)}}{{perSCC|Dickson J}}<br>
+{{CanLIIRP|Abbey|1lpcd|1982 CanLII 25 (SCC)|[1982] 2 SCR 24}}{{perSCC|Dickson J}}<br>
-{{CanLIIR|Mohan|1frt1|1994 CanLII 80 (CanLII)}}{{perSCC|Sopinka J}} at 413 (the opinion must "provide information ‘which is likely to be outside the experience or knowledge of’” the trier of fact")<br>
+{{CanLIIRP|Mohan|1frt1|1994 CanLII 80 (SCC)|[1994] 2 SCR 9}}{{perSCC-H|Sopinka J}} at 413 (the opinion must "provide information ‘which is likely to be outside the experience or knowledge of’” the trier of fact")<br>
-{{CanLIIRP|Bunniss|gcwck|1964 CanLII 673 (BC SC)| (1964), 44 CR 262 (BC Co. Ct.), }}{{perBCSC|Tyrwhitt-Drake J}} (an expert is "one who has by dint of training and practice, acquired a good knowledge of the science or art concerning which his opinion is sought, and the practical ability to use his judgment in that science")<br>
+{{CanLIIRP|Bunniss|gcwck|1964 CanLII 673 (BC SC)| (1964), 44 CR 262 (BC Co. Ct.)}}{{perBCSC|Tyrwhitt-Drake J}} (an expert is "one who has by dint of training and practice, acquired a good knowledge of the science or art concerning which his opinion is sought, and the practical ability to use his judgment in that science")<br>
 </ref>
 The expert must have special knowledge in the matter
 <ref>
-{{CanLIIRP|Terceira|6gmx|1998 CanLII 2174 (ON CA)|, (1998) 123 CCC 1 (Ont. CA)}}{{perONCA|Finlayson JA}}
+{{CanLIIRP|Terceira|6gmx|1998 CanLII 2174 (ON CA)|123 CCC 1 (Ont. CA)}}{{perONCA|Finlayson JA}}
 {{supra1|Mohan}}{{atp|414}} (the witness must be “shown to have acquired special or peculiar knowledge through study or experience in respect of the matters on which he or she undertakes to testify”)
 </ref>
@@ Line 18: / Line 20: @@
 <ref>
 {{supra1|Mohan}}<br>
-{{CanLIIR|Lovie|6jjw|1995 CanLII 801 (ON CA)}}{{perONCA|Finlayson JA}}<br>
+{{CanLIIRP|Lovie|6jjw|1995 CanLII 801 (ON CA)|100 CCC (3d) 68}}{{perONCA|Finlayson JA}}<br>
 </ref>
 There must also be no exclusionary rules that would otherwise prohibit the evidence from being given. <ref>
-{{CanLIIR|NO|22ms4|2009 ABCA 75 (CanLII)}}{{TheCourtABCA}}{{atL|22ms4|19}}<br>
+{{CanLIIRP|NO|22ms4|2009 ABCA 75 (CanLII)|186 CRR (2d) 60}}{{TheCourtABCA}}{{atL|22ms4|19}}<br>
+</ref>
+The use of expert evidence in litigation is essential, especially in cases that involve "highly technical areas" that could not be litigated without assistance.<REf>
+{{CanLIIRPC|Whitfield v. Whitfield|gsp2p|2016 ONCA 581 (CanLII)|401 DLR (4th) 128}}{{TheCourtONCA}} ("There is no question that expert evidence is essential to the litigation process and that many cases involving highly technical areas could not be tried without")<br>
+{{CanLIIRP|Abbey|259rl|2009 ONCA 624 (CanLII)|246 CCC (3d) 301}}{{perONCA-H|Doherty JA}}{{atL|259rl|73}}, leave to appeal to SCC refused<br>
 </ref>
 ; Burden of Proof
 The presumption for any given witness is that an opinion evidence is not admissible.<Ref>
-{{CanLIIRC|Abbott and Haliburton Company v WBLI Chartered Accountants|fxl0z|2013 NSCA 66 (CanLII)}}{{perNSCA|MacDonald CJ}} (dissenting on other issue){{atL|fxl0z|24}}
+{{CanLIIRPC|Abbott and Haliburton Company v WBLI Chartered Accountants|fxl0z|2013 NSCA 66 (CanLII)|361 DLR (4th) 659}}{{perNSCA|MacDonald CJ}} (dissenting on other issue){{atL|fxl0z|24}}
 </ref>
 ; Specialized Knowledge Vs Expert Opinion
-A person testifying to specialized to technical knowledge will not necessarily be required to be qualified as an expert. Where they testify to their "factual knowledge" based on their "knowledge, observations and experience".<ref>
+A person testifying to specialized to technical knowledge will not necessarily be required to be qualified as an expert. Where they testify to their "factual knowledge" based on their "knowledge, observations and experience."<ref>
-{{CanLIIR|Hamilton|fljvz|2011 ONCA 399 (CanLII)}}{{TheCourtONCA}}{{AtsL|fljvz|273| to 284}} - evidence from phone company as to the mechanical workings of cell towers and their relationship to the cell phone<br>
+{{CanLIIRP|Hamilton|fljvz|2011 ONCA 399 (CanLII)|271 CCC (3d) 208}}{{TheCourtONCA}}{{AtsL|fljvz|273| to 284}} - evidence from phone company as to the mechanical workings of cell towers and their relationship to the cell phone<br>
-{{CanLIIR|Ranger|2db2k|2010 ONCA 759 (CanLII)}}{{TheCourtONCA}} -- cell phone tower evidence<br>
+{{CanLIIRP|Ranger|2db2k|2010 ONCA 759 (CanLII)|OJ No 4840}}{{TheCourtONCA}} -- cell phone tower evidence<br>
-cf. {{CanLIIR|Korski|236fj|2009 MBCA 37 (CanLII)}}{{perSCC|Steel JA}} -- required expert to testify on cell tower evidence<br>
+{{contra}} {{CanLIIRP|Korski|236fj|2009 MBCA 37 (CanLII)|244 CCC (3d) 452}}{{perSCC-H|Steel JA}} -- required expert to testify on cell tower evidence<br>
-{{CanLIIR|Potter||2020 NSCA 9 (CanLII)}}{{AtsL||441| to 423}}<br>
+{{CanLIIRx|Potter|j528d|2020 NSCA 9 (CanLII)}}{{TheCourtNSCA}}{{AtsL|j528d|441| to 423}}<br>
-{{CanLIIR|Ajise||2018 ONCA 494 (CanLII)}}{{atL||23}}<br>
+{{CanLIIRP|Ajise|hsb9t|2018 ONCA 494 (CanLII)|361 CCC (3d) 384}}{{atL|hsb9t|23}}<br>
-{{CanLIIR|MacDonald||2020 NSCA 69 (CanLII)}}{{AtL||58}}{{perNSCA|Derrick JA}} (“ Technical evidence grounded in experience, without more, does not constitute expert evidence.”)<br>
+{{CanLIIRx|MacDonald|jb95g|2020 NSCA 69 (CanLII)}}{{AtL|jb95g|58}}{{perNSCA|Derrick JA}} (“ Technical evidence grounded in experience, without more, does not constitute expert evidence.”)<br>
 </ref>
@@ Line 44: / Line 51: @@
 An expert who testifies to direct observation without opinion is not subject to the opinion rule of exclusion. This evidence is admitted in the same way as eye-witness evidence.<ref>
-{{CanLIIR|KA|1f9pr|1999 CanLII 3793 (ON CA)}}{{perONCA|Charron JA}}{{atL|1f9pr|72}}<br>
+{{CanLIIRP|KA|1f9pr|1999 CanLII 3793 (ON CA)|137 CCC (3d) 225}}{{perONCA|Charron JA}}{{atL|1f9pr|72}}<br>
 </ref>
 The expert is not to testify to facts, but rather only opinion to allow the trier-of-fact to draw inferences.
 <ref>
-''R v Parrott'',  [http://canlii.ca/t/523h 2001 SCC 3] (CanLII), [2001] 1 SCR 178{{perSCC|Binnie J}}<br>
+{{CanLIIRP|Parrott|523h|2001 SCC 3 (CanLII)|[2001] 1 SCR 178}}{{perSCC-H|Binnie J}}<br>
-{{CanLIIR|Lavallee|1fsx3|1990 CanLII 95 (CanLII)}}{{perSCC|Wilson J}}
+{{CanLIIRP|Lavallee|1fsx3|1990 CanLII 95 (SCC)|[1990] 1 SCR 852}}{{perSCC|Wilson J}}
 </ref>
@@ Line 59: / Line 66: @@
 ; Specialization
-The key requirement for expert evidence is that the expert "possesses special knowledge and experience going beyond that of the trier of fact".<ref>
+The key requirement for expert evidence is that the expert "possesses special knowledge and experience going beyond that of the trier of fact."<ref>
-{{CanLIIRP|Béland|1ftm1|1987 CanLII 27 (SCC)|, [1987] 2 SCR 398}}{{perSCC|McIntyre J}}{{atp|415}}<br>
+{{CanLIIRP|Béland|1ftm1|1987 CanLII 27 (SCC)|[1987] 2 SCR 398}}{{perSCC-H|McIntyre J}}{{atp|415}}<br>
-{{CanLIIR|Marquard|1frx2|1993 CanLII 37 (CanLII)}}{{perSCC|McLachlin J}}{{atL|1frx2|35}}<br>
+{{CanLIIRP|Marquard|1frx2|1993 CanLII 37 (SCC)|[1993] 4 SCR 223}}{{perSCC-H|McLachlin J}}{{atL|1frx2|35}}<br>
-{{CanLIIRP|Chan|2d9sb|1993 ABCA 383 (CanLII)|, (1993), 145 A.R. 304}}{{TheCourtABCA}}{{atL|2d9sb|9}}<br>
+{{CanLIIRP|Chan|2d9sb|1993 ABCA 383 (CanLII)|145 AR 304}}{{TheCourtABCA}}{{atL|2d9sb|9}}<br>
 </ref>
 As long as the court is satisfied that the witness is sufficiently experienced he should be qualified.<ref>
@@ Line 73: / Line 80: @@
 The means by which the skill, expertise, or knowledge was acquired goes to weight and not admissibility.<ref>
 {{ibid1|Chan}}{{atL|2d9sb|9}} citing Sopinka, Lederman and Bryant, The Law of Evidence of Canada (1992){{atps|536‑537}}: ("As long as the court is satisfied that the witness is sufficiently experienced in the subject matter at issue, the court will not be concerned with whether his or her skill was derived from specific studies or by practical training, although that may affect the weight to be given to the evidence.")<br>
-{{CanLIIRP|Rayner|4v87|2000 NSCA 143 (CanLII)|, 189 N.S.R. (2d) 144}}{{perNSCA|Saunders JA}}
+{{CanLIIRP|Rayner|4v87|2000 NSCA 143 (CanLII)|189 NSR (2d) 144}}{{perNSCA|Saunders JA}}
 </ref>
 It is acceptable to obtain the ability to give an opinion from study, instruction, practical experience or observations. Formal study in not necessary.<ref>
-{{CanLIIRP|Melaragni|gcw35|1992 CanLII 12764 (ON SC)|, (1992), 73 CCC (3d) 348 (Ont. Ct. Gen. Div.), }}{{perONCA|Moldaver JA}}<br>
+{{CanLIIRP|Melaragni|gcw35|1992 CanLII 12764 (ONSC)|73 CCC (3d) 348}}{{perONCA|Moldaver JA}}<br>
-{{CanLIIR|NO|22ms4|2009 ABCA 75 (CanLII)}}{{TheCourtABCA}}{{atL|22ms4|22}}<br>
+{{CanLIIRP|NO|22ms4|2009 ABCA 75 (CanLII)|186 CRR (2d) 60}}{{TheCourtABCA}}{{atL|22ms4|22}}<br>
+</ref>
+; Specialization and Usurpation of the Court
+Specialization brings with it a risk that the jury "will inappropriately defer to the expert’s opinion rather than carefully evaluate it."<ref>
+{{CanLIIRPC|Parliament v Conley|jfkp5|2021 ONCA 261 (CanLII)|155 OR (3d) 161}}{{perONCA|Harvison Young JA}}{{atL|jfkp5|43}}<br>
+{{CanLIIRPC|White Burgess Langille Inman v. Abbott and Haliburton Co||2015 SCC 23 (CanLII)|[2015] 2 SCR 182}}{{AtL||17}}<br>
+{{CanLIIRP|Mohan||1994 CanLII 80 (SCC)|[1994] 2 SCR 9}}, at pp. 21-22
+</ref>
+Courts must be wary of the "allure of scientific infallibility" that creates the risk of the evidence "swallow[ing] whole the fact-finding function of the court."<ref>
+{{supra1|Whitfield}} at para 47<br>
+{{supra1|Abbey}}, at para. 71
+</reF>
+Courts must be vigilent to draw a "firm line" between the role of the expert and the court..<Ref>
+{{supra1|Whitfield}} at para 47<br>
+J-LJ at para 25 to 26<Br>
+</ref>
+The closer the opinion is to the ultimate question for the court to determine the stricter limitations that must be placed on the evidence.<ref>
+{{supra1|Whitfield}} at para 47<br>
+J-LJ at para 37
 </ref>
 ; Jury Instruction
-Where a qualified expert gives opinion evidence outside of their field, the problem can generally be remedied through a "remedial instruction advising the jury to disabuse their minds of the inadmissible evidence".<ref>
+Where a qualified expert gives opinion evidence outside of their field, the problem can generally be remedied through a "remedial instruction advising the jury to disabuse their minds of the inadmissible evidence."<ref>
-{{CanLIIR|Sekhon|g35qf|2014 SCC 15 (CanLII)}}{{perSCC|Moldaver J}}{{atL|g35qf|48}}<br>
+{{CanLIIRP|Sekhon|g35qf|2014 SCC 15 (CanLII)|[2014] 1 SCR 272}}{{perSCC-H|Moldaver J}}{{atL|g35qf|48}}<br>
 </ref>
 ; Standard of Review
 Trial judges are entitled to "wide discretion" and deference when weighing the costs and benefits of admitting expert evidence.<ref>
-{{CanLIIR|Clark|gnqq1|2016 ABCA 72 (CanLII)}}{{TheCourtABCA}}{{atsL|gnqq1|59| to 62}}<br>
+{{CanLIIRx|Clark|gnqq1|2016 ABCA 72 (CanLII)}}{{TheCourtABCA}}{{atsL|gnqq1|59| to 62}}<br>
-{{CanLIIR|DD|525r|2000 SCC 43 (CanLII)}}{{perSCC|Major J}}{{atL|525r|13}}<br>
+{{CanLIIRP|DD|525r|2000 SCC 43 (CanLII)|[2000] 2 SCR 275}}{{perSCC-H|Major J}}{{atL|525r|13}}<br>
-{{CanLIIR|Soni|gsqz9|2016 ABCA 231 (CanLII)}}{{TheCourtABCA}} (2:1){{atL|gsqz9|8}}<br>
+{{CanLIIRP|Soni|gsqz9|2016 ABCA 231 (CanLII)|339 CCC (3d) 294}}{{TheCourtABCA}} (2:1){{atL|gsqz9|8}}<br>
-{{CanLIIR|Dominic|gpltp|2016 ABCA 114 (CanLII)}}{{TheCourtABCA}}{{atL|gpltp|17}}<br>
+{{CanLIIRP|Dominic|gpltp|2016 ABCA 114 (CanLII)|335 CCC (3d) 178}}{{TheCourtABCA}}{{atL|gpltp|17}}<br>
-{{CanLIIR|Abbey|259rl|2009 ONCA 624 (CanLII)}}{{perONCA|Doherty JA}}{{atL|259rl|97}}, leave to appeal to SCC refused<br>
+{{CanLIIRP|Abbey|259rl|2009 ONCA 624 (CanLII)|246 CCC (3d) 301}}{{perONCA-H|Doherty JA}}{{atL|259rl|97}}, leave to appeal to SCC refused<br>
 </ref>
 Whether someone can be qualified as an expert is a question of law and is reviewable on a standard of correctness.<ref>
-{{CanLIIRP|Bear (C.W.)|g1p31|2013 MBCA 96 (CanLII)|, }}{{perMBCA|Steel JA}}{{atL|g1p31|81}}<br>
+{{CanLIIRP|Bear (C.W.)|g1p31|2013 MBCA 96 (CanLII)|299 Man R (2d) 175}}{{perMBCA|Steel JA}}{{atL|g1p31|81}}<br>
+</ref>
+The admission of expert opinion is reviewable on the standard of correctness.<ref>
+{{CanLIIRP|Grandinetti|4pvr|2003 ABCA 307 (CanLII)|178 CCC (3d) 449}}{{perABCA|McFadyen JA}}{{AtsL|4pvr|90}} aff’d, {{CanLIIR|1jmfq|2005 SCC 5 (CanLII)}}<br>
+{{CanLIIRP|Leinen|g01l8|2013 ABCA 283 (CanLII)|301 CCC (3d) 1}}{{AtL|g01l8|21}}<br>
+</ref>
+However, absent error in principle, the reviewing court should be reluctant to interfere with the trial judge's decision.<REf>
+{{CanLIIRP|Andres|dwc|2003 ABCA 333 (CanLII)|112 CRR (2d) 117}}{{perABCA|Fraser ACJ}}{AtL|dwc|21}}<Br>
+{{CanLIIRP|B(CR)|1fswk|1990 CanLII 142 (SCC)|[1990] 1 SCR 717}}{{perSCC|McLachlin J}}{{atL|1fswk|29}}<br>
+{{supra1|Leinen}}{{atL|g01l8|21}}
 </ref>
 {{Reflist|2}}
@@ Line 112: / Line 148: @@
 ===Opinion Evidence Outside of Qualification===
-Where a qualified expert testifies to matters directly outside of their area of qualification but is clearly within their area of special knowledge, the evidence can still be accepted absent any objection to the evidence by the opposing side.<ref>
+Where a qualified expert testifies to matters directly outside of their area of qualification but is clearly within their area of special knowledge, the evidence can still be accepted, absent any objection to the evidence by the opposing side.<ref>
-{{CanLIIR|Marquard|1frx2|1993 CanLII 37 (CanLII)}}{{perSCC|McLachlin J}}{{atps|242-44}}</ref>
+{{CanLIIRP|Marquard|1frx2|1993 CanLII 37 (SCC)|[1993] 4 SCR 223}}{{perSCC-H|McLachlin J}}{{atps|242-44}}</ref>
 Likewise, a technical failure to qualify someone who clearly has expertise in the area, absent any objections, should be permitted to give expert evidence.<ref>
 {{ibid1|Marquard}}{{atps|242-44}}</ref>
@@ Line 122: / Line 158: @@
 There is some difference in opinion of whether or not expert qualification is needed to present evidence from cell phone towers.<ref>
-{{CanLIIR|Hamilton|fljvz|2011 ONCA 399 (CanLII)}}{{TheCourtONCA}}{{atsL|fljvz|273| to 284}} - evidence from phone company as to the mechanical workings of cell towers and their relationship to the cell phone. However, they did not give evidence triangulating the location of the accused's phone.<br>
+{{CanLIIRP|Hamilton|fljvz|2011 ONCA 399 (CanLII)|271 CCC (3d) 208}}{{TheCourtONCA}}{{atsL|fljvz|273| to 284}} - evidence from phone company as to the mechanical workings of cell towers and their relationship to the cell phone. However, they did not give evidence triangulating the location of the accused's phone.<br>
-{{CanLIIR|Ranger|2db2k|2010 ONCA 759 (CanLII)}}{{TheCourtONCA}} -- cell phone tower evidence accepted without qualification for ''general'' location evidence<br>
+{{CanLIIRP|Ranger|2db2k|2010 ONCA 759 (CanLII)|OJ No 4840}}{{TheCourtONCA}} -- cell phone tower evidence accepted without qualification for ''general'' location evidence<br>
-cf. {{CanLIIR|Korski|236fj|2009 MBCA 37 (CanLII)}}{{perMBCA|Steel JA}} -- required expert to testify on cell tower evidence<br>
+cf. {{CanLIIRP|Korski|236fj|2009 MBCA 37 (CanLII)|244 CCC (3d) 452}}{{perMBCA|Steel JA}} -- required expert to testify on cell tower evidence<br>
 </ref>
 It is generally accepted that even where it is not necessary, it is useful to explain some of the records.<ref>
-e.g. {{CanLIIR|McBean|flkp7|2011 ONSC 3125 (CanLII)}}{{perONSC|Fuerst J}}<br>
+e.g. {{CanLIIRx|McBean|flkp7|2011 ONSC 3125 (CanLII)}}{{perONSC|Fuerst J}}<br>
 </ref>
 Evidence on the regular functioning of social media websites can in circumstances be accepted without qualification.<ref>
-{{CanLIIR|Soh|g50jc|2014 NBQB 20 (CanLII)}}{{perNBQB|LaVigne J}}
+{{CanLIIRP|Soh|g50jc|2014 NBQB 20 (CanLII)|1079 APR 328}}{{perNBQB|LaVigne J}}
 </ref>
 {{reflist|2}}
-==Case Digests==
-* [[Expert Evidence (Evidence Cases)]]
 ==See Also==
 * [[Model Examinations (Evidence)]]
 * [[Precedents, Court Forms and Checklists]]