
    UNITED STATES, Appellee, v. Roberto ROSALES, Defendant, Appellant.
    No. 92-1732.
    United States Court of Appeals, First Circuit.
    Heard March 9, 1994.
    Decided March 31, 1994.
    
      Lydia Lizarribar-Masini, Hato Rey, PR, for appellant.
    Miguel A. Pereira, Asst. U.S. Atty., Hato Rey, PR, with whom Guillermo Gil, U.S. Atty., Washington, DC, and José A. Quiles-Espinosa, Sr. Litigation Counsel, Hato Rey, PR, were on brief, for appellee.
    Before SELYA, Circuit Judge, BOWNES, Senior Circuit Judge, and CYR, Circuit Judge.
   BOWNES, Senior Circuit Judge.

Defendant-appellant Roberto Rosales appeals his conviction for abusive sexual contact in violation of 18 U.S.C. § 2244(a)(1). He argues that the district court abused its discretion by admitting explanatory expert witness testimony, and that remarks contained in the prosecutor’s closing argument deprived him of a fair trial. In addition, defendant challenges his sentence on the ground that the district court’s upward departure from the Sentencing Guidelines was unreasonable. We affirm defendant’s conviction, but vacate his sentence and remand the case for resentencing.

I.

BACKGROUND

Defendant is a former elementary school teacher at Antilles Elementary School, located at Fort Buchanan, Puerto Rico. The school is administered by the United States Navy. Complaints of inappropriate touching led to an investigation of defendant, which resulted in an indictment charging him with six counts of abusive sexual contact involving three minor victims. The charges arose from allegations that defendant had touched, kissed and rubbed against three of his former students.

Each victim was a student of defendant for one school year, and all three testified that numerous incidents of sexual contact occurred throughout their time in the third grade. The government also presented the expert testimony of Dr. Nancy Slicner, a child psychologist, who testified about the general behavioral characteristics exhibited by victims of child sexual abuse.

The jury found defendant guilty as charged. The trial judge sentenced defendant to 120 months imprisonment on each count, with the sentences to run concurrently. This appeal ensued.

II.

DISCUSSION

A. Expert Testimony

Defendant first argues that the district court erroneously admitted the expert testimony of Dr. Slicner, a child psychologist who testified for the government. More precisely, defendant argues that the expert testimony should have been excluded because it improperly bolstered the testimony of the minor victims, and therefore its probative value was outweighed by its prejudicial effect. At trial, however, no objection was made to the admissibility of Dr. Slicner’s testimony. Therefore, any error in the admission of the evidence was not preserved for appeal. See United States v. Castro-Lara, 970 F.2d 976, 980 (1st Cir.1992), cert. denied, — U.S. -, 113 S.Ct. 2935, 124 L.Ed.2d 684 (1993); United States v. Serrano, 870 F.2d 1, 10 n. 9 (1st Cir.1989); see also Fed.R.Evid. 103(a)(1). Our standard of review under the circumstances is “plain error,” see United States v. Figueroa, 976 F.2d 1446, 1453 (1st Cir.1992), cert. denied, — U.S. -, 113 S.Ct. 1346, 122 L.Ed.2d 728 (1993), and we will reverse only if the error ‘“seriously affect[ed] the fairness, integrity or public reputation of [the] judicial proceeding[ ].’ ” United States v. Geer, 923 F.2d 892, 896 (1st Cir.1991) (quoting United States v. Young, 470 U.S. 1, 15, 105 S.Ct. 1038, 1046, 84 L.Ed.2d 1 (1985) (internal quotation marks and citation omitted)); see United States v. Olivio-Infante, 938 F.2d 1406, 1411 (1st Cir.1991) (under “plain error” review we will reverse only where a miscarriage of justice has occurred).

Defendant focuses his argument on Dr. Sliener’s testimony that the way in which the minor victims discussed the incidents of sexual abuse with her was consistent with the manner generally exhibited by children who have been sexually abused or molested. Dr. Slicner explained that children generally “tend to be reluctant, they tend to be embarrassed, uncomfortable, ashamed of what happened. They’re very uncomfortable giving details. I see a lot of that. And I saw that in these children.”

Defendant relies on the Ninth Circuit’s decision in United States v. Binder, 769 F.2d 595 (9th Cir.1985), where the court held that the district court erroneously admitted expert testimony addressed directly to the credibility of the abused children. The court found reversible error because,

“[t]he testimony of the experts ... was not limited to references to psychological literature or experience or to a discussion of a class of victims generally. Rather the experts testified that these particular children in this particular case could be believed. The jury in effect was impermissi-bly being asked to accept an expert’s determination that these particular witnesses were truthful.”

United States v. Antone, 981 F.2d 1059, 1062 (9th Cir.1992) (quoting Binder, 769 F.2d at 602). According to the court, the effect of the experts’ testimony was to “bolster the children’s story and to usurp the jury’s fact-finding function.” Id. In Binder, however, the court conducted a “harmless error” review, a standard far less demanding than that of “plain error.”.

Although trial judges are afforded significant leeway in determining whether otherwise admissible evidence is unfairly prejudicial under Fed.R.Evid. 403, see United States v. Spinosa, 982 F.2d 620, 628-29 (1st Cir.1992), we have recognized that “proffered expert testimony [ejould create a substantial danger of undue prejudice ... because of its aura of special reliability and trustworthiness.” United States v. Fosher, 590 F.2d 381, 383 (1st Cir.1979) (collecting cases); accord United States v. Boney, 977 F.2d 624, 631 (D.C.Cir.1992).

We agree with defendant that Dr. Slicner’s testimony sent an implicit message to the jury that the children had testified truthfully, and this might therefore have interfered with the jury’s function as the sole assessor of witness credibility. But, even assuming (without deciding) that the district court improperly calibrated its scales in balancing the probative value of this testimony against its prejudice to defendant, any error was not “plain.”

Our conclusion is based on two factors. First, defendant offered the testimony of its own expert, a child psychiatrist, who sought to undermine the credibility of Dr. Slicner. According to defendant’s expert, the interviews conducted by Dr. Slicner of the children were too short to allow Dr. Slicner to assess their stories accurately. In addition, defendant’s expert stated that the children’s trial testimony, which she listened to attentively, was not consistent with testimony that one would expect from victims of child abuse. Second, the district court instructed the jury as follows:

During the trial you heard the testimony ... of Dr. Nancy Slicner who was presented by the government ... [a]nd we also heard the testimony of Dr. Martinez Lugo presented by the defendant_ If scientific or technical or other specialized knowledge may assist[ ] the juror in understand[ing] the evidence or determining facts in issue, a witness qualified as an expert ... may testify before the jury and state an opinion concerning such matters. Now merely because an expert witness has expressed an opinion does not mean, however, that you as jurors must accept this opinion.
The same as with any other witness. It is up to you to decide whether you believe the testimony of the expert and choose to rely upon it.

Trial Transcript, Vol. XIV at pp. 864-65 (emphasis added).

Not only was the jury presented with expert testimony directly contradicting the objectionable testimony offered by Dr. Slicner, but, the court expressly instructed the jurors that they were free to reject the opinions offered by the experts. Under the circumstances, we are not persuaded that Dr. Slic-ner’s testimony was so prejudicial to defendant “as to undermine the fundamental fairness of the trial and contribute to a miscarriage of justice.” Geer, 923 F.2d at 897 (internal quotation marks and citation omitted).

B. Improper Argument

Defendant next contends that comments by the prosecutor to the jury during closing arguments deprived him of a fair trial. According to defendant, the prosecutor impermissibly vouched for the credibility of the government’s witnesses in his response to defense counsel’s argument that the FBI had fabricated evidence. The prosecutor ' stated:

Then they are also implying here, the defense is implying that there is some kind of conspiracy, that the FBI wanted to fabricate a case against Mr. Rosales, a school teacher at Antilles Elementary School. Like the FBI would have a special interest in this man. But for you to believe that story, you [w]ould also have to believe that the United States, Mr. Pereira [the other AUSA] and myself are part of that conspiracy. And that we would blend [sic] ourselves to do something such as improper and unethical conduct.

Defense counsel objected to this remark. The court sustained the objection, and warned the prosecutor that “[t]he evidence has to do with the participation of the FBI agents [in gathering evidence],” and that he should not go beyond the evidence. No curative instruction was requested by the defense, and none was given. Moreover, defendant did not move for a mistrial.

When a prosecutor places the credibility of counsel at issue, the advantage lies solidly with the government, and thus, prosecutors are prohibited from doing so. See United States v. Cresta, 825 F.2d 538, 555 (1st Cir.1987), cert. denied, 486 U.S. 1042, 108 S.Ct. 2033, 100 L.Ed.2d 618 (1988); see also United States v. Nickens, 955 F.2d 112, 121 (1st Cir.) (prosecutor may not express personal assurances about conclusions to be drawn from the evidence), cert. denied, — U.S. -, 113 S.Ct. 108, 121 L.Ed.2d 66 (1992); United States v. Rodriguez-Estrada, 877 F.2d 153, 158 (1st Cir.1989) (same); United States v. Mejia-Lozano, 829 F.2d 268, 273 (1st Cir.1987) (same). Because this is precisely what the prosecutor in this case did, there is no doubt that his argument was improper. And, the government concedes this. Nevertheless, a new trial is not warranted.

The question is whether the prosecutor’s argument was sufficiently prejudicial to warrant a new trial under the circumstances. This requires that we engage in the functional equivalent of the familiar “harmless error” analysis. See United States v. Brown, 938 F.2d 1482, 1489 (1st Cir.), cert. denied, — U.S. -, 112 S.Ct. 611, 116 L.Ed.2d 633 (1991); Rodriguez-Estrada, 877 F.2d at 159; Fed.R.Crim.P. 52(a). In determining whether the prosecutor’s remark was harmless, “we consider a range of factors, starting with the nature of the prosecutor’s (mis)conduct and ending with the unavoidable bottom line: whether we deem it likely, or not, that any prejudice affected the outcome of the case.” Rodriguez-Estrada, 877 F.2d at 159. In conducting this analysis, we evaluate the prosecutor’s comments in the context of the trial as a whole, not in isolation. See id.; see also Nickens, 955 F.2d at 121. While we have no doubt that the prosecutor’s argument was wholly inappropriate, which is conceded by the government on appeal, reversal is not warranted for the following reasons:'

First, the prosecutor did not repeatedly place his credibility in issue, or extend his argument beyond the scope of the evidence. His improper statement was an isolated one and, as such, was less likely to impact the outcome of the case. See Brown, 938 F.2d at 1489; Mejia-Lozano, 829 F.2d at 274. Second, the issue of the credibility of the government’s witnesses, particularly the children, was fully developed at trial, and the jury was instructed that they alone were charged with judging the credibility of each witness. This diminishes any likelihood that the jury was swayed by the prosecutor’s “vouching.” See Cresta, 825 F.2d at 556.

Next, although the court did not explicitly instruct the jury to disregard the prosecutor’s improper remark, it sustained defendant’s objection and immediately warned the prosecutor (in the presence of the jury) that defendant’s allegations concerned misconduct only by the FBI, and that his argument should be limited to the evidence.

Finally, the trial court repeatedly instructed the jury as to the proper role of argument in the case. Prior to counsel’s opening statements, again before their summations, and once again in its charge, the court explained to the jury that the attorney’s arguments were not evidence, and that only the testimony of the witnesses and admitted documents were evidence. See, e.g., Brown, 938 F.2d at 1489 (instruction that arguments , of counsel are not evidence can remove prejudicial taint of improper argument); United States v. de Leon Davis, 914 F.2d 340, 345 (1st Cir.1990) (same). Although there are circumstances where such an instruction may not be sufficient given the nature of the prosecutor’s argument, see Arrieta-Agressot v. United States, 3 F.3d 525, 529 (1st Cir.1993) (court’s instruction that arguments of counsel are not evidence not enough to counteract prejudice from emotionally charged summation where “the danger was not so much that the jury would consider the prosecutor’s remarks to be ‘evidence.’ Rather, the threat was that the prosecutor’s remarks would excite the jury, invite a partisan response, and distract its attention from [the merits of the case].”), such circumstances are not present here.

We have reviewed the transcripts of the trial testimony in this case, in addition to the briefs, and are convinced that the objectionable remark, viewed in context, and in light of the court’s instructions to the jury, did not affect the outcome of the trial. Defendant’s trial lasted for ten days, and each party was afforded one hour in which to deliver its summation. It is highly unlikely that the jury’s verdict could have been the result of this brief remark by the prosecutor. We conclude that the verdict was based upon the testimony, and the jury’s belief that the government’s witnesses were credible.

Defendant also argues that the prosecutor, in other portions of his summation, improperly vouched for the credibility of government witnesses and commented on facts not in evidence. We have carefully reviewed the prosecutor’s closing argument and rebuttal, and find that these statements were not improper. . The allegedly improper statements are little more than words and phrases taken out of context from the prosecutor’s argument. When the allegedly improper statements are read in full and in context, we can find nothing objectionable about them. Furthermore, because no contemporaneous objection was made, our review is only for plain error. Arrieta-Agressot, 3 F.3d at 528; United States v. Smith, 982 F.2d 681, 682 (1st Cir.1993); Nickens, 955 F.2d at 121. Under the “plain error” standard, we could not order a new trial based.on these remarks. See United States v. Soto-Alvarez, 958 F.2d 473, 477 (1st Cir.) (improper argument constitutes plain error only if it “ ‘undermine[s] the fundamental fairness of the trial and contribute^] to a miscarriage of justice.’ ” (quoting United States v. Soto-Alvarez, 876 F.2d 209, 233 (1st Cir.1989), cert. denied, 493 U.S. 1030, 110 S.Ct. 742, 107 L.Ed.2d 760 (1990))), cert. denied, — U.S. -, 113 S.Ct. 221, 121 L.Ed.2d 159 (1992).

C. The Upward Departure

In sentencing defendant, the district court calculated a Sentencing Guidelines offense level of 22 as follows: the “abusive sexual contact” base offense level of ten, U.S.S.G. § 2A3.4(a)(3); plus six levels because none of the victims had attained the age of twelve, id. § 2A3.4(b)(l);. plus four levels as a multiple count adjustment, id. § 3D1.4; plus two levels based on defendant’s abuse of a position of trust in a manner that facilitated commission of the offense, id. §.3B1.3. The court then placed the defendant into Criminal History Category I. These calculations produced a Guideline Sentence range of forty-one to fifty-one months imprisonment. Id. ch. 5, part A (Sentencing Table). The court then departed upward pursuant to § 5K2.0 of the Sentencing Guidelines, effectively increasing defendant’s offense level to 31, and imposed a prison term of 120 months. Defendant contends that the degree of the upward departure was unreasonable. 18 U.S.C. § 3742(e)(3).

In United States v. Rivera, 994 F.2d 942 (1st Cir.1993), we analyzed the departure powers of sentencing courts under the Guidelines, and recognized that cases which fall outside of the “heartland,” i.e., the “set of typical cases embodying the conduct that each guideline describes,” are candidates for departure. Id. at 947.

At defendant’s sentencing the district court found,

there are aggravating factors in this case_ [T]hat defendant Rosales repeatedly engaged in similar criminal behavior as ... represented by the-counts of the convictions with the minors named in the indictment, conduct for which he was not charged. The evidence at trial showed that defendant engaged in uncharged incidents of abusive sexual contact with minor RG on five occasions, with minor MQ on several occasions and minor VT almost on a daily basis during one school year.

The district court concluded that, “based on multiplicity of incidents of abusive sexual contact that the defendant Roberto Rosales engaged [in] with minors named in the indictment, the Court departs to an offense level of thirty-one.”

The court went on to state that the Guidelines range for offense level thirty-one, where the defendant had a criminal history rating of I, was 120-135 months. This was incorrect. The correct range is 108-135 months. It is unclear whether the court sentenced defendant to 120 months on each count because (1) it meant to sentence defendant at the low end of the incorrect range, or (2) because it intended to impose the statutory maximum for each count. Thus, defendant might very well have been prejudiced by the court’s failure to identify the guideline range the court had in _ mind. But,' because we vacate defendant’s sentence on other grounds, see infra pp. 769-70, we need not pursue this line of thought.

We review a sentencing court’s decision to depart by examining “(1) whether the reasons the court gave for departing are the sort that might permit a departure in an appropriate case; (2) whether the record supports a finding of facts demonstrating the existence of such reasons; and (3) whether, given the reasons, the degree of departure [from about four years to ten] is reasonable.” United States v. Mendez-Colon, 15 F.3d 188, 189 (1st Cir.1994); see United States v. Diaz-Villafane, 874 F.2d 43, 49 (lst Cir.), cert. denied, 493 U.S. 862, 110 S.Ct. 177, 107 L.Ed.2d 133 (1989); Rivera, 994 F.2d at 950.

With respect to the first prong of our analysis, we have recognized that “[s]ome district court decisions that a particular ease is unusual enough to warrant departure reflect sentencing experience of a sort one typically finds in district, not appellate, courts.” United States v. Doe, 18 F.3d 41, 43 (1st Cir.1994). Thus, we review the district court’s determination that a case is unusual, and therefore warrants departure, “with full awareness of, and respect for, the trier’s superior feel for the ease.” United States v. Legarda, 17 F.3d 496, 501 (1st Cir.1994) (quoting Rivera, 994 F.2d at 952 (citations and internal quotation marks omitted)). On the other hand, “where departure decisions reflect a determination of the purpose of, or an interpretation of the language in, a guideline or statute,” plenary review is appropriate. Doe, 18 F.3d at 43.

In the present case, defendant argues merely that, because the indictment covers the entire time period during which defendant’s multiple acts allegedly occurred, an upward departure cannot be based upon these acts. This contention is without merit. Under this indictment, defendant’s offense level would remain the same regardless of whether he engaged in four or four hundred acts of misconduct. The pivotal question is whether the persistent and repetitive nature of defendant’s conduct, charged or uncharged, is an appropriate ground for departure. In other words, is this case “unusual” relative to the garden variety sex offender case? Here, defendant has not challenged the district court’s determination that his casé was outside of the “heartland,” and therefore worthy of an upward departure. Given the respect that we extend to a sentencing court’s determination as to whether a given circumstance makes a case “unusual,” see Doe, 18 F.3d at 43; Rivera, 994 F.2d at 952, we do not believe that the district court erred in its decision to depart from the Guidelines.

As for the second part of our review, the record provides an ample basis for the district court’s conclusion that defendant engaged in multiple acts of misconduct over a prolonged period of time. The frequent and continuous nature of defendant’s conduct is set out in the Pre-Sentence Report. Because no objection was lodged with respect to the PSR’s contents, these facts could be accepted as true and accurate. See United States v. Ramirez, 11 F.3d 10, 14 (1st Cir.1993); United States v. Citro, 938 F.2d 1431, 1445 (1st Cir.1991), cert. denied, — U.S. -, 112 S.Ct. 902, 116 L.Ed.2d 804 (1992) and — U.S. -, 112 S.Ct. 1997, 118 L.Ed.2d 593 (1992). Thus, the district court’s finding of circumstances supporting a departure was not clearly erroneous. See United States v. Mendez-Colon, 15 F.3d 188, 190 (1st Cir.1994).

Finally, we must determine whether the extent of the court’s upward departure was reasonable. See Doe, 18 F.3d at 47-48; 18 U.S.C. § 3742(e)(3) (length of sentence imposed must be reviewed for its “reasonableness”). In examining the reasonableness of a departure, we must consider, inter alia, “the reasons for the imposition of the particular sentence, as stated by the district court....” 18 U.S.C. § 3742(e)(3)(B).

Here the district court articulated the grounds for its upward departure, and then departed upward by nine offense levels, without explaining its choice of this particular figure. Although sentencing courts have substantial “leeway” with respect to the “degree” of a departure, see Doe, 18 F.3d at 48; Rivera, 994 F.2d at 950, this freedom does not relieve a sentencing court from explaining its ultimate decision of how far to depart. See 18 U.S.C. § 3553(c)(2) (sentencing court must state “specific reason[s]” for imposing a “particular sentence” outside of the guideline range); United States v. Ocasio, 914 F.2d 330, 336 (1st Cir.1990) (Generally, a sentencing judge must articulate not only his or her reason for departing ... but must also offer a rationale for the degree of departure.); see also United States v. Kelly, 1 F.3d 1137, 1144 (10th Cir.1993) (“a district court must specifically articulate reasons for the degree of departure. Merely explaining why a departure was made does not fulfill the separate requirement of stating the reasons for imposing the particular sentence.” (citations and internal quotations omitted)). Absent such an explanation, we cannot assess the reasonableness of the court’s nine-level upward departure. Accordingly, defendant’s sentence is vacated, and we remand the case for re-sentencing.

So ordered. 
      
      . Section 2244(a)(1) provides in pertinent part:
      Whoever, in the special maritime and territorial jurisdiction of the United States ... knowingly engages in or causes sexual contact with or by another person, if to do so would violate ... (l) section 2241 of the title had the sexual contact been a sexual act, shall be fined under this title, imprisoned not more than ten years, or both.
      18 U.S.C. § 2244(a)(1). Section 2241(c) makes it a federal crime to engage, or attempt to engage, in a sexual act with a person under the age of twelve, in the territorial jurisdiction of the United States.
     
      
      . Although defendant was originally charged in a six count indictment, two counts were voluntarily dismissed by the government prior to trial,
     
      
      . Were we reviewing the objectionable portion of Dr. Slicner's testimony for harmless error, we would have to decide whether “it can be said ‘with fair assurance, after pondering all that happened without stripping the erroneous action from the whole, that the judgment was not substantially swayed by the error,’ ” United States v. Ladd, 885 F.2d 954, 957 (1st Cir.1989) (quoting Kotteakos v. United States, 328 U.S. 750, 66 S.Ct. 1239, 90 L.Ed. 1557 (1946)).
     
      
      . Under prevailing law, relevant evidence, such as Dr. Slicner’s testimony, is admissible unless its probative value is "substantially outweighed” by the risk of unfair prejudice, confusion, or waste of time. United States v. Argencourt, 996 F.2d 1300, 1305 (1st Cir.1993); Fed.R.Evid. 403.
     
      
      . Section 5K2.0 provides that the sentencing court may impose a sentence outside of the range established by the applicable guideline if the court finds
      that there exists an aggravating or mitigating circumstance of a kind, or to a degree, not adequately taken into consideration by the Sentencing Commission in formulating the Guidelines ■ that should result in a sentence different from that described.
      U.S.S.G. § 5K2.0, p.s. (quoting 18 U.S.C. § 3553(b)).
     
      
      . Given our ruling, we need not reach defendant’s contention that his sentence must be vacated because he was not afforded a reasonable opportunity to review various addenda to the Pre-Sentence Report prior to sentencing.
     