COURT OF APPEALS

DECISION

DATED AND FILED

May 7, 2020

Sheila T. Reiff

Clerk of Court of Appeals

NOTICE

This opinion is subject to further editing. 

If published, the official version will 

appear in the bound volume of the Official 

Reports. 

A party may file with the Supreme Court 

a petition to review an adverse decision by 

the Court of Appeals. See WIS. STAT. § 

808.10 and RULE 809.62. 

Appeal No. 2019AP1261-CR Cir. Ct. No. 2017CF132

STATE OF WISCONSIN IN COURT OF APPEALS

DISTRICT IV

STATE OF WISCONSIN,

 PLAINTIFF-RESPONDENT,

 V.

GARY R. SCHUMACHER,

 DEFENDANT-APPELLANT.

APPEAL from a judgment and an order of the circuit court for 

Monroe County: TODD L. ZIEGLER, Judge. Affirmed.

¶1 KLOPPENBURG, J.1 Gary Schumacher was convicted, upon a jury 

verdict, of operating a motor vehicle with a prohibited alcohol content (OWI-

 

1

 This appeal is decided by one judge pursuant to WIS. STAT. § 752.31(2)(c) (2017-18). 

All references to the Wisconsin Statutes are to the 2017-18 version unless otherwise noted.
No. 2019AP1261-CR

2

PAC) in connection with an accident between Schumacher and another motor 

vehicle.2 Schumacher filed a motion for postconviction relief, alleging that his 

trial counsel was ineffective for failing to adequately cross-examine the State’s 

expert witness who had calculated Schumacher’s blood alcohol content (BAC) at 

the time of the accident, approximately two hours before Schumacher’s blood was 

drawn. The circuit court held a Machner3 hearing and denied the motion, ruling 

that Schumacher had failed to meet his burden of showing either that trial counsel 

performed deficiently or that counsel’s performance prejudiced Schumacher. 

Schumacher appeals. I conclude that Schumacher’s ineffective assistance claim 

fails because he has not met his burden to show deficient performance. Therefore, 

I affirm.

BACKGROUND

¶2 The following facts are undisputed and, except for procedural facts, 

taken from the testimony at trial. 

¶3 At approximately 8:45 p.m. on February 7, 2017, Schumacher was 

involved in a two-vehicle accident in Sheldon, Monroe County. Schumacher 

drove away from the scene of the accident to his residence a short distance away. 

Approximately forty-five minutes later, Sergeant Ryan Lee of the Monroe County 

Sheriff’s Office arrived at the scene of the accident. Lee talked to the occupants of 

the second vehicle and then went to Schumacher’s residence and talked with 

Schumacher.

 

2

 Schumacher was also convicted of a hit and run offense and three non-criminal traffic 

violations, none of which are at issue in this appeal.

3

 State v. Machner, 92 Wis. 2d 797, 285 N.W.2d 905 (Ct. App. 1979).
No. 2019AP1261-CR

3

¶4 Schumacher told Lee that he had consumed one or two beers before 

the accident and that he had also consumed alcohol after the accident, but he did 

not say how much or what kind, and Lee saw no evidence of open intoxicants in 

the residence. Lee ultimately arrested Schumacher for operating a motor vehicle 

while intoxicated and took him to the hospital, where Schumacher’s blood was 

drawn at 10:56 p.m. Schumacher’s BAC at the time his blood was drawn was 

0.171 grams per 100 ml of blood, above the legal limit applicable to him of 0.08.

¶5 The State charged Schumacher with operating a motor vehicle with a 

prohibited alcohol concentration of 0.08 or more, and Schumacher, represented by 

counsel, proceeded to a jury trial. Among those who testified at trial were the 

State’s expert witness Kristin Drewieck, a chemist with the Wisconsin State 

Laboratory of Hygiene, and Schumacher. Pertinent details of Drewieck’s

testimony will be set forth in the discussion below. Summarizing here, Drewieck

provided three estimates of Schumacher’s BAC at the time of the accident, based 

on three different sets of assumptions. 

¶6 The first estimate: Before Schumacher testified, Drewieck testified 

as to her estimate that Schumacher’s BAC at the time of the accident was between 

0.190 and 0.210, using a process called “retrograde extrapolation” to extrapolate

from the result of the test when the blood was drawn at 10:56 p.m., 0.171, to the 

time of the accident approximately two hours earlier. She calculated this estimate 

using an average rate of alcohol elimination and assumptions that the blood was 

drawn from a man who weighed 200 pounds and that the man had consumed no 

alcohol between the time of the accident and the time the blood was drawn.

¶7 After Drewieck testified, Schumacher testified that he consumed 

three Pabst Blue Ribbon beers between 6:00 and 7:30 before the accident, and then 
No. 2019AP1261-CR

4

after the accident he consumed three or four, or maybe seven, beers and two shots 

of whiskey “right before” Lee arrived. Schumacher testified that he threw the beer 

cans in the sink and pointed to the sink when he told Lee he had consumed more 

alcohol since the accident.

¶8 The second estimate: The State called Drewieck to testify as a 

rebuttal witness, where, again using retrograde extrapolation, Drewieck estimated

that Schumacher’s BAC at the time of the accident was between 0.08 and 0.11, 

based on assumptions that the man from whom the blood was drawn at 10:56 

weighed 200 pounds and had consumed three to four beers and two shots of 

whiskey between 8:45, the time of the accident, and 9:30, when Officer Lee 

arrived at Schumacher’s residence.

¶9 The third estimate: Assuming that Schumacher had consumed only 

the beers and not the shots between 8:45 and 9:30, Drewieck estimated that 

Schumacher’s BAC at the time of the accident was between 0.12 and 0.15.

¶10 The jury found Schumacher guilty of OWI-PAC. Schumacher, by 

newly appointed counsel, filed a motion for postconviction relief, alleging that 

trial counsel had provided constitutionally ineffective assistance for failing to 

cross-examine Drewieck regarding the reliability of retrograde extrapolation and 

the assumptions she used to perform her calculations; in support of his motion 

Schumacher cited and provided a 1985 article on the reliability of retrograde 

extrapolation to calculate BAC. The circuit court held a Machner hearing at 

which trial counsel testified. Pertinent details of trial counsel’s testimony will be 

set forth in the discussion below. As stated, the court denied the motion, ruling 

that Schumacher had failed to meet his burden of showing either that trial counsel 
No. 2019AP1261-CR

5

performed deficiently or that his performance prejudiced Schumacher. 

Schumacher appeals.

DISCUSSION

¶11 In well-presented briefing, the parties dispute whether Schumacher 

has met his burden to show that his trial counsel provided constitutionally 

ineffective assistance in his cross-examination of Drewieck. I first summarize the 

applicable standard of review and legal principles, next review additional pertinent 

background, and then explain why I conclude that Schumacher’s ineffective 

assistance of counsel claim fails.

I. Applicable Standard of Review and Applicable Legal Principles

¶12 A defendant claiming ineffective assistance of counsel must show

both that counsel’s performance was deficient and that the deficient performance

prejudiced the defense. Strickland v. Washington, 466 U.S. 668, 687 (1984).

“Whether a defendant received ineffective assistance of counsel is a mixed

question of law and fact.” State v. Maday, 2017 WI 28, ¶25, 374 Wis. 2d 164, 892

N.W.2d 611. The circuit court’s findings of fact will not be disturbed unless those

findings are clearly erroneous. Id. “‘[T]he circumstances of the case and ...

counsel’s conduct and strategy’ are considered findings of fact.” Id. (quoted 

source omitted). However, whether those facts constitute deficient performance 

and whether such deficient performance was prejudicial are questions of law that 

we review independently. See State v. Tulley, 2001 WI App 236, ¶5, 248 Wis. 2d 

505, 635 N.W.2d 807. “[T]here is no reason for a court deciding an ineffective 

assistance claim ... to address both components of the inquiry if the defendant 

makes an insufficient showing on one.” Strickland, 466 U.S. at 697. I decide this 

appeal based on the deficient performance prong.
No. 2019AP1261-CR

6

¶13 Counsel’s performance is “constitutionally deficient if it falls below 

an objective standard of reasonableness.” State v. Thiel, 2003 WI 111, ¶19, 264 

Wis. 2d 571, 665 N.W.2d 305. “The question is whether an attorney’s 

representation amounted to incompetence under ‘prevailing professional norms,’ 

not whether it deviated from best practices or most common custom.” Harrington 

v. Richter, 562 U.S. 86, 105 (2011) (citation omitted). In other words, 

professionally competent assistance encompasses a “wide range” of conduct, and a 

reviewing court starts with the presumption that counsel’s assistance fell within 

that wide range. Strickland, 466 U.S. at 689. “A fair assessment of attorney 

performance requires that every effort be made to eliminate the distorting effects 

of hindsight, to reconstruct the circumstances of counsel’s challenged conduct, and 

to evaluate the conduct from counsel’s perspective at the time.” Id. A defendant’s 

burden is to show that counsel “made errors so serious that counsel was not 

functioning as the ‘counsel’ guaranteed the defendant by the Sixth Amendment.” 

Id. at 687.

II. Additional Pertinent Background

¶14 I now present additional pertinent background comprising the details 

of Drewieck’s testimony and Schumacher’s cross-examination at the trial, trial 

counsel’s testimony at the Machner hearing, and the circuit court’s ruling.

A. Drewieck’s Testimony and Counsel’s Cross-Examination at Trial

1. Drewieck’s Testimony and Counsel’s Cross-Examination Before Schumacher 

Testified

¶15 In her initial testimony, Drewieck testified on direct examination as 

to her training and experience, and the procedures and verification used in 
No. 2019AP1261-CR

7

processing Schumacher’s blood sample. She testified that the BAC of 

Schumacher’s blood sample was 0.171.

¶16 On cross-examination, Schumacher’s trial counsel asked, “You don’t 

know what his BAC was at 8:45 p.m. [the time of the accident], do you?” 

Drewieck responded, “That’s correct. I can make an estimate, but, correct, I do 

not know.”

¶17 On redirect, the State asked Drewieck why the BAC was not 0.171 

at 8:45. Drewieck responded, 

There [are] two processes that are involved in this 

type of scenario. The first is that between 8:45 p.m. and 

10:56 p.m. any alcohol consumed prior to 8:45 is being 

removed, eliminated by the body. 

So even if a person continues to drink alcohol, the 

process of elimination starts as soon as you have any 

alcohol in your bloodstream. So that we have two hours—

approximately two hours of time there where the body is 

removing some of the alcohol that was consumed, okay?

The other process that needs to be accounted for is 

absorption; if there is still absorption that is ongoing in the 

time between 8:45 and 10:56 p.m.

¶18 The prosecutor asked whether Drewieck was able to calculate what 

the BAC would have been at the earlier time, knowing what the BAC was two 

hours later. Drewieck responded,

I can make an estimate, but the estimate I make is 

only as good as the information that goes into the estimate 

so it depends on what kind of information we have 

available....

I would need to know ... as much as possible, what 

the drinking consumption was like; was there a lot of 

drinking between 8:30 and 8:45; was there any continuing 

consumption between 8:45 and 10:56; what—the specific 

individual we’re talking about, are they male—in this case, 

obviously—what their weight is. Food potentially could 
No. 2019AP1261-CR

8

have an impact, if they had a full stomach at the time of 

consumption. Those are the big things.

¶19 The prosecutor asked Drewieck to calculate the BAC at 8:45 p.m. 

for a person who weighed 200 pounds and consumed no additional alcohol 

between 8:45, the time of the accident, and 10:56, when the blood sample showing 

a BAC of .171 was taken. Drewieck responded, “I can give you an estimate ... I 

would estimate that the alcohol concentration would be approximately 0.190 to 

0.210.”

¶20 Asked by the prosecutor to explain her calculations, Drewieck 

testified: 

All I did for this calculation was evaluate how much 

alcohol had been removed from the body during that 

intervening two-hour period, because I was told, assume 

no, you know, continuing absorption, no continuing 

consumption.

So basically there’s a range of elimination. The 

vast majority of people would fall within that range. 

Depending on how frequently a person consumes alcohol, 

if someone is a teetotaler and consumes alcohol very rarely, 

then their body eliminates it much more slowly. A chronic 

consumer, even an alcoholic, can eliminate alcohol pretty 

quickly because their body has gotten more used to it....

For the purposes of these calculations I use kind of 

an average in the middle. I certainly can do a range ... but 

in this case, I used an average elimination rate, which is 

supported by scientific literature, the studies that have been 

done that I talked about earlier.

¶21 Schumacher’s trial counsel asked no further questions.

2. Drewieck’s Rebuttal Testimony and Counsel’s Cross-Examination After 

Schumacher Testified

¶22 The prosecutor called Drewieck as a rebuttal witness and asked her 

if her calculation of an estimate of Schumacher’s BAC at 8:45 p.m. would change 
No. 2019AP1261-CR

9

based on Schumacher’s testimony of his alcohol consumption between the time of 

the accident and the time his blood sample was taken. Drewieck responded that it 

would, “Because under those circumstances, then, we need to basically subtract 

from my previous number the alcohol that was consumed after the [accident]

because obviously if it’s consumed after the [accident] it doesn’t affect what their 

BAC was at the time of [the accident].” She explained that she could make “an 

estimate” based on Schumacher’s testimony regarding his alcohol intake after the 

accident by starting with the known BAC at the time of the blood draw and then 

“accounting for the amount of alcohol that was consumed before the blood was 

drawn but after the [accident].” Drewieck further explained that the new estimates 

she could calculate would take into account the effect that the drinks consumed 

after the accident would have on the test result, because the alcohol consumed 

after the accident cannot be “count[ed] against the person.”

¶23 Drewieck calculated the new estimate and testified that, in doing so, 

she assumed that the subject of her estimate was a 200-pound man who was 

driving a vehicle at 8:45 p.m. and had his blood drawn at 10:56 p.m. showing a 

BAC of 0.171, and who between 8:45 p.m. and 9:30 p.m. drank three to four Pabst 

Blue Ribbon beers and two shots of whiskey. She further explained that she used 

“a standard alcohol concentration for a beer of 4% and ... a standard 100 proof 

one ounce for each shot, okay, and the beer is 12-ounce cans.” Drewieck testified 

that, based on these assumptions, she “would estimate ... the blood alcohol 

concentration at the time of [the accident] would be somewhere between 0.08 and 

0.11.”

¶24 Asked by the prosecutor to calculate an estimate if only the beer and 

no whiskey had been consumed, Drewieck did so and testified that, “If the two 

shots were not consumed and all we’re subtracting from the blood alcohol 
No. 2019AP1261-CR

10

concentration is what the three to four beers would contribute, I would estimate 

that the blood alcohol concentration at the time of [the accident] would be 

approximately 0.12 to 0.15, with the same assumptions that I stated earlier.”

¶25 In response to further questioning by the prosecutor, Drewieck 

testified that it would take “12 to 13 [standard] drinks for a 200-pound male to 

reach 0.171” between 6:30 p.m., approximately when Schumacher testified he 

drank three beers before the accident, and 10:56 p.m., when his blood was drawn.

¶26 Drewieck testified that her BAC calculations were “just an estimate. 

The solid number that we have is the blood alcohol concentration that was 

reported on the sample that was tested in our laboratory.” The prosecutor asked, 

“Is it fair to say that your calculations are only as good as the information is that is 

put into those calculations?” Drewieck responded, “Absolutely.” Drewieck 

concluded her direct examination on rebuttal by testifying, 

[Retrograde extrapolation is] widely used to 

evaluate drinking situations like this. As I’ve stated all 

along, and you [the prosecutor] said yourself, the 

calculation, the estimate is only as good as the information 

that goes into it, and it’s absolutely nowhere near as 

reliable and as solid as the test result itself.

But this type of calculation is based on scientific 

principles of absorption and elimination and how alcohol 

spreads throughout your body. So it’s based on science. 

Depends on how good the information is that I am given.

¶27 On cross-examination, Schumacher’s trial counsel asked Drewieck 

about the different factors that go into the calculation, and she responded, “There 

are lots of factors that go into the calculations like these.” Counsel asked 

Drewieck whether it would make a difference if any of the drinks consumed were 

a twenty-ounce “tall boy” rather than a twelve-ounce can, and she responded, “that 

would certainly make a difference,” as would changing the number of beers 
No. 2019AP1261-CR

11

consumed from three or four to a higher number like seven. Counsel asked 

Drewieck how she arrived at the standard alcohol concentration of 4% for one 

beer, and she responded, “It’s just the number that we use in doing these types of 

calculations. Certainly, beers are higher; some beers are lower. I can use a 

different number ... I just did not know what Pabst Blue Ribbon was offhand.” 

Counsel asked a similar question about the use of 100 proof for the whiskey, and 

she responded that that was also just a number, arrived at by “consider[ing] a 

standard drink [as] one ounce of 100 proof or one and a quarter ounces of 80 

proof” or, in other words, “a perfectly poured shot.”

B. Trial Counsel’s Testimony at the Machner Hearing

¶28 At the Machner hearing, Schumacher’s trial counsel acknowledged 

that the key element of the OWI-PAC offense at trial was Schumacher’s BAC at 

the time of the accident. He testified that he anticipated the expert using 

retrograde extrapolation to calculate Schumacher’s BAC at the time of the 

accident; that he was familiar with the retrograde extrapolation process, with the 

criticisms of its use, and with the variables used in the calculations; that he had 

reviewed books and articles on retrograde extrapolation; that he had consulted 

with his colleagues in the public defender’s office about the expert’s use of the 

process; and that he had tried unsuccessfully to speak to the expert before trial.

¶29 Counsel testified that, when Drewieck initially testified, counsel did 

not on cross-examination ask Drewieck about the BAC calculation because, 

I thought the expert had actually done a pretty good 

job herself of qualifying how she had come to the 

conclusions in ... her testimony. It was ... the fact that she 

had brought up that there were a number of variables, she 

was making guesses. So I didn’t want to beat a dead horse. 

I thought it would be apparent to the jury.
No. 2019AP1261-CR

12

¶30 Counsel further testified,

I believe [Drewieck] had actually addressed why 

the calculation she was making [was] pure conjecture [and] 

if I went up and doubled down on the things that she 

already said, that I didn’t think that would come across well

... there was nothing for me to—anything new for me to 

elicit, and I really just thought she went over the issues 

herself.

¶31 Counsel testified that he asked Drewieck on cross-examination about 

the effect on the calculations of the size and alcohol content of the drinks 

Schumacher consumed, but that he did not ask her about the effect of any food 

consumption by Schumacher or Schumacher’s rate of alcohol elimination. He 

testified that he did not ask Drewieck about these variables because, 

I think the single factor that I was keyed in on is it 

was very late; the trial had gone on for a long time. And, 

being honest, I don’t think it looked like the jury was 

paying attention at all at that point ... I figured I had maybe 

a few questions that they would pay attention to, so I just 

tried to focus on the things that I thought someone in the 

jury would know, like, you know, that’s a really low 

assumption for an alcohol content for a beer or that a shot 

was poured perfectly or in that amount, things like that. I 

figure I had a really limited window to actually make an 

impression on the jury.

¶32 Counsel testified that he agreed in theory that challenging the expert 

on cross-examination was important, but that at the trial, he believed that the 

expert 

seemed very up front about the ... issues themselves 

regarding retrograde [extrapolation] ... I thought she did a 

good job of raising the issues herself. And while I likely 

planned to go more in depth, by the time I got to cross, like 

I said, I just really felt like I had a really limited window to 

make an impression on the jury ... I was just afraid they 

wouldn’t pay attention at all.
No. 2019AP1261-CR

13

C. Circuit Court’s Ruling

¶33 The circuit court concluded that Schumacher had not met his burden 

to show deficient performance. The court found that the record supported trial 

counsel’s belief that Drewieck made “a fair amount of qualifications or indicated 

limitations as to her estimates as to what Mr. Schumacher’s blood alcohol level 

would be.... And [counsel] didn’t feel it was necessary to point out or to do that 

further in front of the jury in concern of potentially alienating the jury.” The court 

found that, after Drewieck made additional calculations based on Schumacher’s 

testimony, counsel on cross focused on a few questions about the issues that the 

jury would have “understood more ... rather than, again, potentially alienating the 

jury.” The court also found that counsel’s questions on cross-examination 

informed the jury that there was no “stipulation to the expert’s calculations.”

¶34 The circuit court found that counsel “clearly understood the issue of 

retrograde extrapolation before the trial started. He addressed it.” The court 

found that, while other attorneys may have engaged in more or less crossexamination, counsel here “had ... strategic reasons as to why he handled the issue 

the way he handled it.” The court concluded that it did not “see anything that was 

outside the professional norms for a defense attorney in an OWI case ... I do 

believe that [counsel’s] actions were within the professional norms.”

¶35 The circuit court also concluded that Schumacher failed to meet his 

burden to show prejudice.

III. Analysis

¶36 Schumacher argues that his trial counsel provided deficient 

performance by inadequately cross-examining Drewieck regarding the reliability 
No. 2019AP1261-CR

14

of retrograde extrapolation and the assumptions she used to calculate 

Schumacher’s BAC at the time of the accident. As shown above, and as the State 

argues in response, the record refutes Schumacher’s argument.

¶37 I first summarize the additional background provided above. 

Through counsel’s cross-examination of Drewieck the first time she testified, 

counsel elicited testimony that the BAC reported at the time of the blood draw was 

not Schumacher’s BAC at the time of the accident two hours earlier, and that 

Drewieck could not know, and could only estimate, Schumacher’s BAC at the 

time of the accident. On redirect examination, Drewieck explained that her 

estimate was only as good as the information that went into the estimate and, thus, 

depended on the information that was available. She then calculated an estimate 

based only on a 200-pound male who eliminated alcohol at an average rate and 

had a BAC of 0.171 two hours after driving. Counsel did not question Drewieck 

further at that point because he believed Drewieck had herself qualified her 

calculations and sufficiently indicated to the jury that she was making guesses.

¶38 When Drewieck on rebuttal calculated estimates of Schumacher’s 

BAC at the time of the accident, based on the alcohol Schumacher testified he 

consumed after the accident, Drewieck again testified that her calculations were 

just estimates that were only as good as the information going into them and were 

“nowhere near as reliable and as solid” as the test result. After Drewieck 

calculated two additional BAC estimates based on Schumacher’s testimony about

his alcohol consumption, Schumacher’s counsel questioned Drewieck on crossexamination regarding her reliance on the variables supporting those two 

estimates. Counsel limited his cross-examination to questioning the accuracy of 

the key variables that Drewieck relied on, and that were most likely to be 

understood by the jury (number, type, and alcohol content of the drinks 
No. 2019AP1261-CR

15

Schumacher consumed after the accident), in order to keep what he perceived as 

the jury’s waning attention and because he believed, again, that Drewieck had 

herself identified the limits of her calculations based on those variables.

¶39 I now explain why the record refutes Schumacher’s deficient 

performance argument. When Drewieck testified, both initially and on rebuttal, 

Schumacher’s counsel made, as the circuit court found, a strategic decision not to 

engage in further questioning regarding the reliability of retrograde extrapolation,

because doing so would elicit repetitive answers at the risk of alienating the jury. 

In addition, a prudent attorney could reasonably decide that further questioning on 

the same points already conceded by Drewieck would also risk Drewieck refining 

her answers so as to soften the degree of guesswork and qualification to which she 

had already admitted. Given that Drewieck had herself effectively acknowledged 

the limits of retrograde extrapolation, both initially and on rebuttal, trial counsel’s 

strategic decision not to further question Drewieck regarding the reliability of 

retrograde extrapolation was both reasonable and well within professional norms. 

¶40 Schumacher does not identify what testimony regarding the limits of 

retrograde extrapolation further questioning would have elicited. Schumacher 

points to the “minimal data” that made Drewieck’s first estimate unreliable, but 

the record shows that Drewieck’s testimony offered on direct and redirect and in 

response to trial counsel’s cross-examination so strongly qualified her estimate 

that the State called her back in rebuttal in an attempt to fill in the gaps she had 

initially identified. Schumacher acknowledges that Drewieck’s subsequent 

estimates provided on rebuttal were based on additional data derived from 

Schumacher’s testimony, but he asserts that certain critical data such as food 

consumption and “whether Schumacher was in the absorption or elimination 

stage” were still missing. However, at trial counsel did challenge the accuracy of 
No. 2019AP1261-CR

16

the variables that Drewieck used, and he did so in a way that would focus the jury, 

whose attention he believed was waning, on variables that the jury would readily 

digest. Schumacher’s assertion that his trial counsel “did not adequately crossexamine [Drewieck] regarding the accuracy of the assumptions she was relying on 

in making her calculations” is belied by the record.

¶41 The circuit court found that counsel made the strategic decision to 

focus on that which the jury would most readily understand and pay attention to. 

Counsel’s cross-examination focused the jury on the deficiencies most directly 

associated with Drewieck’s new estimates, and his strategic decision to do so was 

therefore both reasonable and within professional norms.

¶42 Schumacher analogizes this case to State v. Zimmerman, 2003 WI 

App 196, 266 Wis. 2d 1003, 669 N.W.2d 762. In that case, a DNA expert’s 

testimony suggested that DNA results from samples taken from the scene of a 

homicide were inconclusive, when in fact the test results excluded the defendant 

as a source of the DNA. Id., ¶40. This court ruled that “[c]ounsel’s failure to 

challenge [the expert’s] testimony with this data had the effect of essentially 

stipulating that the evidence was inconclusive,” and was therefore deficient 

performance. Id. Here, however, Schumacher’s trial counsel did challenge 

Drewieck’s testimony, regarding both the unreliability of retrograde extrapolation 

generally and the inaccuracy of certain of the significant variables Drewieck 

specifically used in this case. Here, the circuit court found that counsel’s conduct 
No. 2019AP1261-CR

17

did not amount to a stipulation to Drewieck’s calculations, and the record 

reviewed above supports that finding.4 

¶43 Finally, Schumacher also asserts that trial counsel fell below the 

standard of an ordinarily prudent lawyer by failing “to present evidence that 

experts in the field question the reliability of retrograde extrapolation,” citing 

Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 596 (1993) (“Vigorous 

cross-examination, presentation of contrary evidence, and careful instruction on 

the burden of proof are the traditional and appropriate means of attacking shaky 

but admissible evidence.”). I do not reach this argument because Schumacher 

failed to raise it in his postconviction motion in the circuit court. See Schill v. 

Wisconsin Rapids Sch. Dist., 2010 WI 86, ¶45 & n.21, 327 Wis. 2d 572, 786 

N.W.2d 177 (explaining that issues not raised in the circuit court are forfeited, and 

supporting the proposition that appellate courts generally do not address forfeited 

issues); Schwittay v. Sheboygan Falls Mut. Ins. Co., 2001 WI App 140, ¶16 n.3, 

246 Wis. 2d 385, 630 N.W.2d 772 (stating that “[a] party must raise an issue with 

sufficient prominence such that the [circuit] court understands that it is called upon 

to make a ruling”); Schonscheck v. Paccar, Inc., 2003 WI App 79, ¶11, 261 

Wis. 2d 769, 661 N.W.2d 476 (“A fundamental appellate precept is that we ‘will 

not ... blindside [circuit] courts with reversals based on theories which did not 

originate in their forum.’” (quoting State v. Rogers, 196 Wis. 2d 817, 827, 539 

N.W.2d 897 (Ct. App. 1995)).

 

4

 Schumacher also analogizes this case to State v. Jeannie M.P., 2005 WI App 183, 286 

Wis. 2d 721, 703 N.W.2d 694. In that case, the circuit court found that trial counsel was deficient 

in “fail[ing] to make any effort whatsoever to impeach [a witness’s] testimony corroborating 

[evidence against the defendant].” Id., ¶16. Again, however, here Schumacher’s trial counsel did 

make an effort to cast doubt on Drewieck’s expert testimony.
No. 2019AP1261-CR

18

¶44 In sum, Schumacher’s argument that trial counsel was deficient for 

not adequately cross-examining Drewieck regarding the reliability of retrograde 

extrapolation and the accuracy of the assumptions Drewieck used in her 

calculations fails.

CONCLUSION

¶45 For the reasons stated, Schumacher’s ineffective assistance of trial 

counsel claim fails because he has not met his burden to show that counsel 

performed deficiently. Therefore, I affirm.

By the Court.—Judgment and order affirmed.

This opinion will not be published. See WIS. STAT.

RULE 809.23(1)(b)4.