NE Code § 27-702 (2021)
2021 Nebraska Revised Statutes|Chapter 27 - Courts; Rules of Evidence|27-702 - Rule 702. Testimony by experts; when.

27-702.  Rule 702. Testimony by experts; when.If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.Source  Laws 1975, LB 279, § 50.Annotations  1. When evidence is admissible 2. Evidence allowed 3. Trial court discretion 4. Miscellaneous 1. When evidence is admissible When a court is faced with a decision regarding the admissibility of expert opinion evidence, the trial judge must determine at the outset, pursuant to the evidence rule governing expert witness testimony, whether the expert is proposing to testify to (1) scientific, technical, or other specialized knowledge that (2) will assist the trier of fact to understand or determine a fact in issue. Pitts v. Genie Indus., 302 Neb. 88, 921 N.W.2d 597 (2019). Because the credibility of witnesses is a determination within the province of the trier of fact, testimony that usurps that role is not helpful and thus is improper opinion testimony under section 27-701 and this section. State v. Rocha, 295 Neb. 716, 890 N.W.2d 178 (2017). The abolition of the "ultimate issue rule" does not lower the bar so as to admit all opinions, because under section 27-701 and this section, opinions must be helpful to the trier of fact. State v. Rocha, 295 Neb. 716, 890 N.W.2d 178 (2017). Under section 27-701 and this section, opinion testimony, whether by a lay or expert witness, is permissible only if it is helpful to the trier of fact in making a determination of a fact in issue. State v. Rocha, 295 Neb. 716, 890 N.W.2d 178 (2017). Under this section and sections 27-403 and 27-701, a witness may not give an opinion as to a defendant's guilt or how the case should be decided, but, rather, must leave the conclusions to be drawn by the trier of fact, because such opinions are not helpful. State v. Rocha, 295 Neb. 716, 890 N.W.2d 178 (2017). Under this section and sections 27-602 and 27-701, it is improper for a witness to testify whether another person may or may not have been telling the truth in a specific instance. State v. Rocha, 295 Neb. 716, 890 N.W.2d 178 (2017). A trial court can consider several nonexclusive factors in determining the reliability of an expert's opinion: (1) whether a theory or technique can be (and has been) tested; (2) whether it has been subjected to peer review and publication; (3) whether, in respect to a particular technique, there is a high known or potential rate of error; (4) whether there are standards controlling the technique's operation; and (5) whether the theory or technique enjoys general acceptance within a relevant scientific community. State v. Braesch, 292 Neb. 930, 874 N.W.2d 874 (2016). Absent evidence that an expert's testimony grows out of the expert's own prelitigation research or that an expert's research has been subjected to peer review, experts must show that they reached their opinions by following an accepted method or procedure as it is practiced by others in their field. State v. Braesch, 292 Neb. 930, 874 N.W.2d 874 (2016). Before admitting expert opinion testimony under this section, a trial court must determine whether the expert's knowledge, skill, experience, training, and education qualify the witness as an expert. If an expert's opinion involves scientific or specialized knowledge, a trial court must determine whether the reasoning or methodology underlying the testimony is valid (reliable). It must also determine whether that reasoning or methodology can be properly applied to the facts in issue. State v. Braesch, 292 Neb. 930, 874 N.W.2d 874 (2016). To be admissible, an expert's opinion must be based on good grounds, not mere subjective belief or unsupported speculation. A trial court should not require absolute certainty in an expert's opinion, but it has discretion to exclude expert testimony if an analytical gap between the data and the proffered opinion is too great. State v. Braesch, 292 Neb. 930, 874 N.W.2d 874 (2016). Fundamentally, it is always the burden of the proponent of the evidence to establish the necessary foundation for its admission, including its scientific reliability under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001). State v. Casillas, 279 Neb. 820, 782 N.W.2d 882 (2010). A trial court should admit expert testimony if there are good grounds for the expert's conclusion notwithstanding the judge's belief that there are better grounds for some alternative conclusion. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). Absent evidence that an expert's testimony grows out of the expert's own prelitigation research or that an expert's research has been subjected to peer review, experts must show that they reached their opinions by following an accepted scientific method or procedure as it is practiced by others in their field. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). An expert's opinion must be based on good grounds, not mere subjective belief or unsupported speculation. "Good grounds" mean an inference or assertion derived by scientific method and supported by appropriate validation. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). Before admitting expert opinion testimony, a trial court must determine whether the expert's knowledge, skill, experience, training, and education qualify the witness as an expert. If the opinion involves scientific or specialized knowledge, trial courts must also determine whether the reasoning or methodology underlying the expert's opinion is scientifically valid. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). If the data underlying an expert's opinion involving scientific or specialized knowledge are so lacking in probative force and reliability that no reasonable expert could base an opinion on them, an opinion which rests entirely upon them must be excluded. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). In determining the admissibility of an expert's opinion, the court must focus on the validity of the underlying principles and methodology— not the conclusions that they generate. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). The relevant factors for assessing the reliability or scientific validity of an expert's opinion are whether (1) the theory or technique can be, or has been, tested; (2) the theory or technique has been subjected to peer review and publication; (3) there is a known or potential rate of error; (4) there are standards controlling the technique's operation; and (5) the theory or technique enjoys general acceptance within the relevant scientific community. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). Under the framework set out in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001), the proponent of expert testimony must establish by a preponderance of the evidence that (1) the reasoning or methodology underlying an expert's testimony is scientifically valid and (2) the reasoning or methodology can be properly applied to the facts. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). Expert witness's background and research provided sufficient foundation for her opinion despite her statement that her opinion was her "best guess." Orchard Hill Neighborhood v. Orchard Hill Mercantile, 274 Neb. 154, 738 N.W.2d 820 (2007). Under this section, a witness can testify concerning scientific, technical, or other specialized knowledge only if the witness is qualified as an expert. Jackson v. Brotherhood's Relief & Comp. Fund, 273 Neb. 1013, 734 N.W.2d 739 (2007). An expert's opinion is ordinarily admissible under this section if the witness (1) qualifies as an expert, (2) has an opinion that will assist the trier of fact, (3) states his or her opinion, and (4) is prepared to disclose the basis of that opinion on cross-examination. State v. Gutierrez, 272 Neb. 995, 726 N.W.2d 542 (2007); State v. Robinson, 272 Neb. 582, 724 N.W.2d 35 (2006); In re Interest of Aly T. & Kazlynn T., 26 Neb. App. 612, 921 N.W.2d 856 (2018). In a bench trial, an expert's testimony will be admitted under Neb. Evid. R. 702 and given the weight to which it is entitled. City of Lincoln v. Realty Trust Group, 270 Neb. 587, 705 N.W.2d 432 (2005). A trial court's evaluation of the admissibility of expert opinion testimony is essentially a four-step process. The court must first determine whether the witness is qualified to testify as an expert. It must examine whether the witness is qualified as an expert by his or her knowledge, skill, experience, training, and education. If it is necessary for the court to conduct an analysis under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), then the court must determine whether the reasoning or methodology underlying the expert testimony is scientifically valid and reliable. To aid the court in its evaluation, the judge may consider several factors, including, but not limited to, whether the reasoning or methodology has been tested and has general acceptance within the relevant scientific community. Once the reasoning or methodology has been found to be reliable, the court must determine whether the methodology can properly be applied to the facts in issue. In making this determination, the court may examine the evidence to determine whether the methodology was properly applied and whether the protocols were followed to ensure that the tests were performed properly. Finally, the court determines whether the expert evidence and the opinions related thereto are more probative than prejudicial, as required under Neb. Evid. R. 403, section 27-403. State v. Tolliver, 268 Neb. 920, 689 N.W.2d 567 (2004). An expert does not need to have additional expertise in the science or theory underlying instruments used in his or her field; that the expert is trained to operate a device is sufficient foundation for admitting evidence produced by the device. State v. Aguilar, 268 Neb. 411, 683 N.W.2d 349 (2004). Expert testimony is admissible if it assists the trier of fact to understand the evidence or to determine a fact in issue. State v. Buechler, 253 Neb. 727, 572 N.W.2d 65 (1998). In determining whether an expert's testimony is admissible, a court considers four preliminary and interrelated questions: (1) Whether the witness qualifies as an expert pursuant to this section; (2) whether the expert's testimony is relevant; (3) whether the expert's testimony assists the trier of fact to understand the evidence or determine a controverted factual issue; and (4) whether the expert's testimony, even though relevant and admissible, should be excluded under section 27-403 because its probative value is substantially outweighed by the danger of unfair prejudice or other considerations. Robinson v. Bleicher, 251 Neb. 752, 559 N.W.2d 473 (1997). There are four questions a court considers to determine the admissibility of expert testimony: (1) Does the witness qualify as an expert pursuant to this section? (2) Is the expert's testimony relevant? (3) Will the expert's testimony assist the trier of fact to understand the evidence or to determine a controverted factual issue? (4) Should the expert's testimony, even though relevant and admissible, be excluded in light of section 27-403? State v. Lopez, 249 Neb. 634, 544 N.W.2d 845 (1996). Expert testimony which may be of assistance to the trier of fact is admissible even in areas where laypersons have competence to determine the facts. Coppi v. West Am. Ins. Co., 247 Neb. 1, 524 N.W.2d 804 (1994). Expert testimony concerning a question of law is generally not admissible in evidence. Schmidt v. Omaha Pub. Power Dist., 245 Neb. 776, 515 N.W.2d 756 (1994). If an expert's testimony lacks probative value, the testimony is irrelevant and is inadmissible. In determining admissibility of an expert's testimony, a court considers four questions: (1) Does the witness qualify as an expert? (2) Is the testimony relevant? (3) Will the testimony assist the trier of fact to understand the evidence or determine a controverted factual issue? (4) Should the testimony, even if relevant and admissible, be excluded in light of section 27-403? Relevance of an opinion is among the initial questions for a trial court in determining admissibility of an expert's opinion under this section. Reliability of an expert's testimony which is based on a scientific principle or on a technique or process which applies a scientific principle depends on general acceptance of the principle, technique, or process in the relevant scientific community. Under the standard of helpfulness required by this section, a court may exclude an expert's opinion which is nothing more than an expression of how the trier of fact should decide a case or what result should be reached on any issue to be resolved by the trier of fact. When an expert's opinion on a disputed issue is a conclusion which may be deduced equally as well by the trier of fact with sufficient evidence on the issue, the expert's opinion is superfluous and does not assist the trier in understanding the evidence or determining a factual issue. Whether a witness is an expert depends on the factual basis or reality behind a witness's title or underlying a witness's claim to expertise. Whether a witness is qualified to testify as an expert under this section is a preliminary question of admissibility for a trial court under section 27-104(1). State v. Reynolds, 235 Neb. 662, 457 N.W.2d 405 (1990). The first question to be answered by a court considering admissibility of expert testimony under this section is whether the testimony is likely to assist the trier of fact; if the testimony will not be of assistance to the jury in its deliberations and relates to an area within the competency of ordinary citizens, the expert testimony is not admissible. Getzschman v. Miller Chemical Co., 232 Neb. 885, 443 N.W.2d 260 (1989). Evidence of a test result cannot be characterized as "scientific" or qualify as "technical or other specialized knowledge," and thus within the purview of this provision, unless and until it is established that the test result demonstrates what it is claimed to demonstrate. State v. Borchardt, 224 Neb. 47, 395 N.W.2d 551 (1986). Expert testimony should not be received if it appears the witness is not in possession of such facts as will enable him to express a reasonably accurate conclusion as distinguished from a mere guess or conjecture. The witness should not be allowed to express an opinion on an inadequate basis or in respect to facts not disclosed to the jury. Priest v. McConnell, 219 Neb. 328, 363 N.W.2d 173 (1985). Expert testimony which may be of assistance to the trier of fact is admissible even in areas where laymen have competence to determine the facts. Hegarty v. Campbell Soup Co., 214 Neb. 716, 335 N.W.2d 758 (1983). The general rule is that expert testimony is admissible only if it will be of assistance to the jury in its deliberations and relates to an area not within the competency of ordinary citizens. State v. Ammons, 208 Neb. 812, 305 N.W.2d 812 (1981). Before an expert opinion can be rendered, it must be shown that such an opinion is based upon scientific, technical, or other specialized knowledge which would assist the trier of fact to understand the evidence or to determine a fact in issue, and that the witness qualifies as an expert by reason of knowledge, skill, experience, training, or education. Northern Nat. Gas Co. v. Beech Aircraft Corp., 202 Neb. 300, 275 N.W.2d 77 (1979). Whether one qualifies as an expert depends on the factual basis or reality underlying the witness's title or claim to expertise. The standard of care is not based on the title of the physician, but, rather, on the substance of the treatment. Testimony of qualified medical doctors cannot be excluded simply because they are not specialists in a particular school of medical practice. Instead, experts or skilled witnesses will be considered qualified if, and only if, they possess special skill or knowledge respecting the subject matter involved so superior to that of persons in general as to make the expert's formation of a judgment a fact of probative value. Hoffart v. Hodge, 9 Neb. App. 161, 609 N.W.2d 397 (2000). 2. Evidence allowed In a trial for attempted murder, assault, and other crimes, the State's forensic expert was qualified to testify regarding gunshot residue found on the defendant's clothing, despite the fact that the expert did not have personal knowledge regarding the manner in which calibration substances or standards were manufactured; rather, it was enough that the expert was trained on gunshot residue testing and was qualified to accurately perform the tests. State v. Aguilar, 268 Neb. 411, 683 N.W.2d 349 (2004). The testimony of a guardian ad litem in a custody modification proceeding was erroneously admitted as expert testimony when there was no showing she possessed any scientific, technical, or other specialized knowledge which would assist the trier of fact to understand the evidence or determine a fact in issue. Heistand v. Heistand, 267 Neb. 300, 673 N.W.2d 541 (2004). Trial court did not err in allowing police officer to testify as to how long THC remains in a person's system where the officer possessed extensive experience in the area of illegal narcotics and had received specific training in drug testing processes from a qualified examiner. Trial court did not err in allowing police officer to testify that a substance was marijuana where the officer had received approximately 20 hours of training in drug identification and illegal drugs and 100 hours of additional instruction in criminal investigation and evidence, the officer was experienced in undercover drug investigations and other drug control efforts, and his testimony was corroborated by a forensic chemist. State v. Stahl, 240 Neb. 501, 482 N.W.2d 829 (1992). An architect's assessment that sidewalks are safer to walk on than grass is not the kind of determination which requires special skill, knowledge, or experience to make, as contemplated by this provision. Johannes v. McNeil Real Estate Fund VIII, 225 Neb. 283, 404 N.W.2d 424 (1987). Testimony by a criminal investigator concerning fingerprints found at the scene of the crime is admissible, when relevant, as expert testimony. State v. Birge, 223 Neb. 761, 393 N.W.2d 713 (1986). Remarks by the treating physician to the effect that the causes of aneurysmal bone cyst recurrences were largely unknown did not make his expert opinion as to the cause underlying plaintiff's recurrence inadmissible; the remarks were available for impeachment and were properly weighed by the trier of fact. Goers v. Bud Irons Excavating, 207 Neb. 579, 300 N.W.2d 29 (1980). For a qualified expert to give an opinion of the speed of a vehicle, all necessary factors needed to establish an opinion should be supported by evidence. Nickal v. Phinney, 207 Neb. 281, 298 N.W.2d 360 (1980). Self-styled retired burglar permitted to testify for State as expert for opinion on utility of articles in possession of defendant when apprehended. State v. Briner, 198 Neb. 766, 255 N.W.2d 422 (1977). Auto manufacturer's expert witness entitled to present illustrative experiment and to testify regarding an ultimate issue of fact. Shover v. General Motors Corp., 198 Neb. 470, 253 N.W.2d 299 (1977). Sufficient foundation existed for a doctor's expert opinion in his affidavit that a nursing home's actions or inactions did not cause a resident's injuries and subsequent death, so that the opinion could be considered by the trial court when deciding a motion for summary judgment where the affidavit and attached curriculum vitae established that the doctor, board certified in family and geriatric medicine, had regularly cared for residents of assisted living facilities and was qualified to evaluate the cause of injuries and death. Apkan v. Life Care Centers of America, 26 Neb. App. 154, 918 N.W.2d 601 (2018). The trial court's admission of testimony by banker as expert witness regarding security agreement was not an abuse of discretion. Skiles v. Security State Bank, 1 Neb. App. 360, 494 N.W.2d 355 (1992). 3. Trial court discretion In a bench trial, a trial court is not required to conclusively determine whether an expert's opinion is reliable before admitting the expert's testimony, because the court is not shielding the jury from unreliable evidence. The court has discretion to admit a qualified expert's opinion subject to its later determination after hearing further evidence that the opinion is unreliable and should not be credited. State v. Braesch, 292 Neb. 930, 874 N.W.2d 874 (2016). A trial court does not have discretion to permit a witness who has not been qualified as an expert to testify to issues that require an expert’s opinion. Simon v. Drake, 285 Neb. 784, 829 N.W.2d 686 (2013). A trial court, when faced with an objection under Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001), must adequately demonstrate by specific findings on the record that it has performed the gatekeeping duty imposed by this section. A trial court adequately demonstrates that it has performed its gatekeeping duty when the record shows (1) the court's conclusion whether the expert's opinion is admissible and (2) the reasoning the court used to reach that conclusion, specifically noting the factors bearing on reliability that the court relied on in reaching its determination. Zimmerman v. Powell, 268 Neb. 422, 684 N.W.2d 1 (2004). An appellate court reviews the record de novo to determine whether a trial court has abdicated the gatekeeping function imposed by this section; when the trial court has not abdicated its gatekeeping function, an appellate court reviews the trial court's decision to admit or exclude the evidence for an abuse of discretion. Zimmerman v. Powell, 268 Neb. 422, 684 N.W.2d 1 (2004). In performing its gatekeeping duty, the trial court's discretion extends to deciding what factors are reasonable measures of reliability in each case. Zimmerman v. Powell, 268 Neb. 422, 684 N.W.2d 1 (2004). The trial court does not have the discretion to abdicate its gatekeeping duty imposed by this section. Zimmerman v. Powell, 268 Neb. 422, 684 N.W.2d 1 (2004). In performing its gatekeeping duty, the trial court has considerable discretion in deciding what procedures to use in determining if an expert's testimony satisfies. Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001). When a court is faced with a decision regarding the admissibility of expert opinion evidence, the trial judge must determine at the outset, pursuant to this section, whether the expert is proposing to testify to (1) scientific, technical, or other specialized knowledge that (2) will assist the trier of fact to understand or determine a fact in issue. This entails a preliminary assessment whether the reasoning or methodology underlying the testimony is valid and whether that reasoning or methodology properly can be applied to the facts in issue. Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001). The trial court initially determines whether expert testimony will assist the trier of fact. Ketteler v. Daniel, 251 Neb. 287, 556 N.W.2d 623 (1996). When a trial court is faced with an offer of a novel form of expertise, the trial court must determine whether the new technique or principle is sufficiently reliable. Evidence of a test result cannot be characterized as "scientific" or "technical" until it is established that the test result demonstrates what it claimed to demonstrate. State v. Dean, 246 Neb. 869, 523 N.W.2d 681 (1994). A trial court's ruling in receiving or excluding an expert's testimony which is otherwise relevant will be reversed only when there has been an abuse of discretion. McDonald v. Miller, 246 Neb. 144, 518 N.W.2d 80 (1994). No exact standard is possible for fixing the qualifications of an expert or skilled witness, who will be deemed qualified if, and only if, he or she possesses special skill or knowledge respecting the subject matter involved so superior to that of men in general as to make his or her formation of a judgment a fact of probative value. A trial court's factual finding that a witness qualifies as an expert will be upheld on appeal unless clearly erroneous. Brown v. Farmers Mut. Ins. Co., 237 Neb. 855, 468 N.W.2d 105 (1991). A trial court's factual finding pursuant to section 27-104(1) concerning a determination whether a witness qualifies as an expert under this section will be upheld on appeal unless clearly erroneous. The determination whether an expert's testimony or opinion will be helpful to a jury or assist the trier of fact involves the discretion of a trial court, whose ruling will be upheld on appeal unless the court abused its discretion. State v. Reynolds, 235 Neb. 662, 457 N.W.2d 405 (1990). Absent an abuse of discretion, a trial judge's ruling regarding the admissibility of expert testimony will not be reversed. Palmer v. Forney, 230 Neb. 1, 429 N.W.2d 712 (1988). It is within the trial court's discretion to determine whether there is sufficient foundation for an expert witness to give his opinion about an issue in question. Edwards v. Mount Moriah Missionary Baptist Church, 21 Neb. App. 896, 845 N.W.2d 595 (2014). A trial court adequately demonstrates that it has performed its gatekeeping duty in determining the reliability of expert testimony when the record shows (1) the court's conclusion whether the expert's opinion is admissible and (2) the reasoning the court used to reach that conclusion, specifically noting the factors bearing on reliability that the court relied on in reaching its determination. Kirkwood v. State, 16 Neb. App. 459, 748 N.W.2d 83 (2008). The mental health board did not abuse its discretion in receiving the opinion of a licensed psychologist on the subject's mental health when the psychologist evaluated the subject, qualified as an expert, and had an opinion which would assist the board. In re Interest of Michael U., 14 Neb. App. 918, 720 N.W.2d 403 (2006). There is no exact standard for determining when one qualifies as an expert, and a trial court's factual finding that a witness qualifies as an expert will be upheld on appeal unless clearly erroneous. It is within the trial court's discretion to determine if there is sufficient foundation for a witness to give his or her opinion about an issue in question. A trial court's ruling in receiving or excluding an expert's opinion which is otherwise relevant will be reversed only when there has been an abuse of discretion. Hoffart v. Hodge, 9 Neb. App. 161, 609 N.W.2d 397 (2000). 4. Miscellaneous In a bench trial, an expert's testimony will be admitted and given the weight to which it is entitled. Reiber v. County of Gage, 303 Neb. 325, 928 N.W.2d 916 (2019). The trial court erred in permitting the plaintiff’s treating physician to testify against the plaintiff in a medical malpractice case when the physician had not been qualified as an expert. The ruling allowed the physician to provide expert testimony while denying the plaintiff an opportunity to discover facts related to the physician’s qualifications and the data underlying his opinions. The error was not harmless because jurors were likely to give more weight to the plaintiff’s own treating physician testifying against him. Simon v. Drake, 285 Neb. 784, 829 N.W.2d 686 (2013). The horizontal gaze nystagmus test involves scientific knowledge and falls generally under the rules of Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001). State v. Casillas, 279 Neb. 820, 782 N.W.2d 882 (2010). To sufficiently call specialized knowledge into question under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001), is to object with enough specificity so that the court understands what is being challenged and can accordingly determine the necessity and extent of any pretrial proceeding. State v. Casillas, 279 Neb. 820, 782 N.W.2d 882 (2010). Trial courts are not required to delve into every possible error in the data underlying an expert's opinion involving scientific or specialized knowledge unless it is raised by the party opposing the admission of the expert's opinion. King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009). The first portion of analysis under Daubert v. Merrell Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001), establishes the standard of reliability; the second portion assesses whether the scientific evidence will assist the trier of fact to understand the evidence or determine a fact in issue by providing a valid scientific connection to the pertinent inquiry as a precondition to admissibility. McNeel v. Union Pacific RR. Co., 276 Neb. 143, 753 N.W.2d 321 (2008). Under the analysis in Daubert v. Merrell Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001), expert testimony lacks "fit" when a large analytical leap must be made between the facts and the opinion. McNeel v. Union Pacific RR. Co., 276 Neb. 143, 753 N.W.2d 321 (2008). Neb. Evid. R. 702 is part of a statutory scheme that governs the admissibility at trial of expert opinion testimony regarding the value of real estate. City of Lincoln v. Realty Trust Group, 270 Neb. 587, 705 N.W.2d 432 (2005). The objective of the gatekeeping responsibility imposed by this section is to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field. Schafersman v. Agland Coop, 268 Neb. 138, 681 N.W.2d 47 (2004). It is not enough for the trial court to determine that an expert's methodology is valid in the abstract. The trial court must also determine if the witness has applied the methodology in a reliable manner. Carlson v. Okerstrom, 267 Neb. 397, 675 N.W.2d 89 (2004). It is not enough that a witness is qualified as an expert. The trial court must also act as a gatekeeper to ensure the evidentiary relevance and reliability of the expert's opinion. Carlson v. Okerstrom, 267 Neb. 397, 675 N.W.2d 89 (2004). For trials commencing on or after October 1, 2001, in trial proceedings, the admissibility of expert opinion testimony under the Nebraska rules of evidence should be determined based upon the standards first set forth in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993). Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001). This section provides the requirements for admission of expert opinion testimony. Gittins v. Scholl, 258 Neb. 18, 601 N.W.2d 765 (1999). The trial court erred in admitting the expert testimony of an economist on the issue of hedonic damages, as the economist did not qualify as an expert pursuant to this section. Anderson/Couvillon v. Nebraska Dept. of Soc. Servs., 248 Neb. 651, 538 N.W.2d 732 (1995). Trial court erred in permitting police officer to testify as to administration of his various interrogation techniques. State v. Welch, 241 Neb. 699, 490 N.W.2d 216 (1992). All conflicts in the evidence, expert or lay, and the credibility of the witnesses are for the jury and not the Supreme Court on review. Palmer v. Forney, 230 Neb. 1, 429 N.W.2d 712 (1988). An allegation that an expert offered false testimony will not be sustained on a mere difference of expert opinion, and where opinion evidence of experts is in conflict, it becomes a question for the jury. Palmer v. Forney, 230 Neb. 1, 429 N.W.2d 712 (1988). The determination of the truthfulness or accuracy of an expert's conclusions is for the jury. Palmer v. Forney, 230 Neb. 1, 429 N.W.2d 712 (1988). Under these provisions, it is no longer necessary to have formal training in order to be considered as an expert witness; actual practical experience in the field can also qualify one as an expert in that field. State v. Hoxworth, 218 Neb. 647, 358 N.W.2d 208 (1984). Under sections 27-702 and 27-705, an expert witness, qualified to be such, may testify in terms of opinion or inference without prior disclosure of underlying facts or data, the weight of such evidence being for the trier of facts. State v. Journey, 201 Neb. 607, 271 N.W.2d 320 (1978). Possible modification of rule relating to opinion of investigator as to point of impact discussed but not applied retrospectively. Rawlings v. Andersen, 195 Neb. 686, 240 N.W.2d 568 (1976). The trial court's admission of a doctor's testimony regarding "grooming" in a sexual assault of a child case, without performing its gatekeeping function under the Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v. Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001), framework, was prejudicial error. State v. Edwards, 28 Neb. App. 893, 949 N.W.2d 799 (2020). An individual's summary judgment affidavit was not sufficient to meet the requirements to qualify him as an expert in regard to whether a roofing contractor's repairs were defective; the affidavit failed to set forth sufficient foundation for his opinion, because he included no references to his occupation, training, experience, qualifications, or education, and he failed to accurately describe the property he inspected and the methodology he employed during such inspection. Edwards v. Mount Moriah Missionary Baptist Church, 21 Neb. App. 896, 845 N.W.2d 595 (2014). A medical expert's testimony concerning causes of the plaintiff's multiple myeloma was properly excluded. King v. Burlington Northern Santa Fe Ry. Co., 16 Neb. App. 544, 746 N.W.2d 383 (2008). No analysis pursuant to Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), is necessary where the party asserting error does not challenge the scientific validity and reliability of the guidelines set forth in the Manual on Uniform Traffic Control Devices. Kirkwood v. State, 16 Neb. App. 459, 748 N.W.2d 83 (2008). A person appointed as guardian ad litem is not necessarily an expert on child welfare. The primary function of a guardian ad litem's report is for the guardian to demonstrate to the judge that the guardian has performed his or her duty. When a guardian ad litem's report does not contain objectionable hearsay, it is an efficient means of communicating the facts that the guardian has learned to the parties and to the judge, if properly admitted into evidence, but a report is not somehow made admissible because it was prepared by a guardian ad litem appointed by a court pursuant to a statute. Hearsay within such reports remains hearsay. Joyce S. v. Frank S., 6 Neb. App. 23, 571 N.W.2d 801 (1997). In a prosecution for sexual assault of a child, an expert witness may not give testimony which directly or indirectly expresses an opinion that the child is believable, that the child is credible, or that the witness' account has been validated. State v. Doan, 1 Neb. App. 484, 498 N.W.2d 804 (1993).