OPINION

The United States appeals the district court’s decision to grant defendant Robert Parish an eight-level downward departure from the sentence prescribed by the Sentencing Guidelines after Parish pleaded guilty to two counts of possession of child pornography in violation of 18 U.S.C. § 2252A(a)(5)(B). In imposing the sentence, the district court gave two reasons for its downward departure. First, the district court found that Parish’s conduct was “outside of the heartland” of the offense. Second, the district court concluded that Parish was highly susceptible to abuse in prison. Because we find no abuse of discretion in the district court’s rulings, we affirm the sentence.

FACTUAL AND PROCEDURAL HISTORY

Parish worked for a company based in Bozeman, Montana. In May of 1999, Parish’s employer terminated his employment because it discovered that he was spending considerable time on the Internet and had abused his travel expenses. Parish returned a laptop computer that his employer had provided to him for use in his job.

While cleaning out the laptop’s hard drive, another employee discovered files on the hard drive that appeared to contain child pornography. After consulting with legal counsel, the company turned the computer over to the Bozeman Police Department, which in turn sent the computer to the FBI.

The FBI analyzed Parish’s laptop computer and found that, from November 1998 through May 1999, Parish had routinely visited numerous pornographic sites, some of which included child pornography. When Parish visited these sites, files were automatically downloaded into the Temporary Internet Cache folder on the hard drive. Pictures go into the Temporary Internet Cache folder when they appear on the screen, whether the user wants them or not, unlike intentionally downloaded pictures. Approximately 9,000 images were found on Parish’s hard drive, including 1,300 images that appeared to be child pornography. Although the vast majority of these images depicted adolescent girls, some images depicted graphic, violent sexual exploitation of very young children.

Parish was arrested for possessing and receiving child pornography. After his arrest, FBI agents seized the computer that Parish was using at his new job. Again, analysis of that computer yielded evidence that Parish had visited numerous pornographic websites, including some sites with pornographic images of children. In addition, a search of Parish’s e-mail account revealed an exchange of messages with a 15 year-old female high school student in North Carolina.

*1028 There was no evidence on either computer that Parish had actively downloaded and stored any of the images. Nor was there any organization of the child pornography images or retrieval system for such images on either computer.

Parish was indicted on two counts of Possession of Child Pornography, 18 U.S.C. § 2252A(a)(5)(B), and two counts of Receiving Child Pornography, 18 U.S.C. § 2252A(a)(2). He reached an agreement with the government in which he pleaded guilty to two counts of Possession of Child Pornography. In preparation for sentencing, the probation department calculated that Parish’s offense level was 20 and that his criminal history category was I. The probation department did not recommend a departure from the prescribed guideline range of thirty-three to forty-one months.

The district court held a lengthy sentencing hearing. Parish’s father-in-law, mother-in-law, neighbor, and wife testified on his behalf. Dr. Michael Joseph Scolat-ti, a clinical psychologist and the co-director of the sex-offender treatment unit at the Missoula Regional Prison, also testified on Parish’s behalf. Dr. Scolatti had examined Parish, and he testified at length about the minimal likelihood of recidivism in Parish’s case and about the relative seriousness of Parish’s conduct, as compared to the conduct of other offenders. Dr. Scolatti concluded that Parish’s conduct was less culpable than the conduct of the “eight [or] nine” other child pornography offenders in the federal system with whom Dr. Scolatti was familiar. After comparing Parish’s conduct to the conduct of both sex offenders in general and child-pornography possessors in particular, Dr. Scolatti opined that Parish’s conduct was “outside the heartland” of the offense.

The government also presented testimony from several witnesses. The government focused on three images found on Parish’s computers that were particularly graphic or violent, two of which depicted children who appeared to be about six years old. The government also stressed that Parish had taken steps to act on his fantasies by exchanging e-mails with the North Carolina girl. Finally, the government presented testimony that Parish had icons on his desktop that served as “short cuts” to pornography sites.

After the government presented its case, the district court recalled Dr. Scolatti. Dr. Scolatti testified that nothing he had heard from the government’s witnesses changed his view. He again opined that Parish’s conduct was outside the “heartland” of the offense.

Ultimately, the district court departed downward eight levels in sentencing Parish. The court relied on Dr. Scolatti’s testimony and determined that Parish’s conduct was outside the heartland of U.S.S.G. § 2G2.4, which applies to possession of child pornography. 1 In addition, the district court determined that “[Parish’s] stature, his demeanor, his naivete, the nature of the offense, ... the combination of all of those things” created “a high susceptibility of abuse in prison.” The court sentenced Parish to sixteen months on each count, with the sentences to run concurrently. The court determined that eight months of that sentence would be *1029 spent in prison, and the other eight months would be “served by home detention with electronic monitoring.” Citing the application note to U.S.S.G. § 5C1.1, the district court stated that it was fashioning a sentence incorporating house arrest in order to meet a specific treatment purpose. 2

The government appealed the sentence. 3 There is no challenge to the conviction.

DISCUSSION

We review for abuse of discretion a district court’s decision to depart from the Sentencing Guidelines. United States v. Sablan, 114 F.3d 913, 916 (9th Cir.1997) (en banc). We accord substantial deference to the district court’s decision to depart, because “it embodies the traditional exercise of discretion by a sentencing court.” Koon v. United States, 518 U.S. 81, 98 , 116 S.Ct. 2035 , 135 L.Ed.2d 392 (1996). We review de novo the district court’s interpretation of the Guidelines and review for clear error the factual findings underlying the sentencing decision. United States v. Jeter, 236 F.3d 1032, 1034 (9th Cir.2001).

A district court may depart from the applicable Guideline range if it 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 (policy statement) (quoting 18 U.S.C. § 3553 (b)). In Koon , the Supreme Court explained how a district court should decide whether to depart from the range prescribed in the particular Guideline. 518 U.S. at 93-94 , 116 S.Ct. 2035 . First, the district court should identify what features of the case make it unusual. Id. at 95 , 116 S.Ct. 2035 . Next, the court must determine whether the ground on which it is contemplating a departure is forbidden, encouraged, or discouraged by the Guidelines. Id. The court may not depart on a forbidden ground. Id. at 95-96 , 116 S.Ct. 2035 . The court may depart on an encouraged ground as long as that encouraged ground is not already taken into account by the particular offense guideline. Id. at 96 , 116 S.Ct. 2035 . If a factor is discouraged, or encouraged but already taken into account, the district court may depart only if the factor is “present to an exceptional degree or in some other way makes the case different from the ordinary case where the factor is present.” Id. If the Guidelines do not mention the factor t all, a district court must consider whether this particular factor warrants departure. Id.

The district court here concluded that a downward departure was warranted on two grounds, one arising from characteristics of the offense and the other arising from the characteristics of the offender. See U.S.S.G. § 5K2.0 (policy statement) (describing departure factors as “offense” or “offender” characteristics). As for the former, the court concluded that Parish’s conduct was outside the “heartland” — the *1030 set of typical cases — that the applicable Guideline, U.S.S.G. § 2G2.4, was intended to punish. As for the latter, the district court concluded that Parish’s likely susceptibility to abuse in prison warranted a departure. We will discuss each issue in turn.

The “Heartland” of the Offense of Possessing Child Pornography

In United States v. Stevens, 197 F.3d 1263 (9th Cir.1999), we discussed the “heartland” of the offense of possessing child pornography. In Stevens , the district court made two errors of law. First, it measured the defendant’s conduct against the reasons Congress enacted the statute prohibiting child pornography, instead of measuring the defendant’s conduct against that of other offenders. Id. at 1268-69 . Second, the court relied on the fact that the defendant had not committed other crimes (such as child molestation) in addition to possession of child pornography. Id. at 1269 . We held that the court must base its determination on the nature of the defendant’s conduct in comparison with the conduct of other offenders of the same statute, and that the “heartland” to be determined is the heartland of the offense of possessing child pornography. Id. at 1268-69 .

Here, the district court performed precisely the inquiry that we set out in Stevens . The district court asked Dr. Sco-latti to compare Parish’s conduct with the conduct of a “typical” offender under this same statute. Dr. Scolatti concluded that Parish’s conduct was significantly less serious than that of offenders in other cases involving possession of child pornography. Among other things, Dr. Scolatti noted that Parish had not affirmatively downloaded the pornographic files, indexed the files, arranged them in a filing system, or created a search mechanism on his computer for ease of reference or retrieval. Rather, he testified, the images in Parish’s possession had been downloaded automatically into his Temporary Internet Cache file.

Dr. Scolatti also described the content of the images in Parish’s possession as “pretty minor” compared to the content of images possessed by other offenders. Dr. Scolatti described Parish’s conduct as “on the minimal end” of the scale, when compared to the conduct of a typical child-pornography offender. 4 Dr. Scolatti testified that most of the individuals convicted under the federal child pornography possession statute with whom he was familiar had been “a lot more extreme in terms of what they’ve done with child pornography and the Internet.” After the district court correctly explained to Dr. Scolatti the concept of the “heartland” of an offense, the doctor opined that Parish’s conduct was “outside of the heartland, definitely.” At the close of the sentencing hearing, after hearing the government’s evidence, Dr. Scolatti reaffirmed that opinion.

On the basis of Dr. Scolatti’s testimony and on the court’s own sentencing experience, the district court determined that Parish’s conduct was outside the heartland of the offense targeted by the Guideline. The district court did not abuse its discretion in making that determination. The court appropriately compared Parish’s pos-sessory conduct with the possessory conduct of the typical child-pornography offender, and the record supports the court’s *1031 conclusion that Parish’s conduct was comparatively minor.

Even if reasonable minds could differ, we cannot say that the district court abused its discretion in determining that Parish’s offense conduct was outside the heartland. To the extent that the evidence conflicted, it was up to the district court to resolve those conflicts. United States v. Working, 224 F.3d 1093, 1102 (9th Cir.2000) (en banc).

Susceptibility to Abuse in Prison

A defendant’s unusual susceptibility to abuse by other inmates while in prison may warrant a downward departure. Koon, 518 U.S. at 111-12 , 116 S.Ct. 2035 ; United States v. Lara, 905 F.2d 599, 603 (2d Cir.1990). The district court found that Parish was susceptible to abuse in prison because of a “combination” of factors: “his stature, his demeanor, his naivete, [and] the nature of the offense.”

The reason for the district court’s consideration of Parish’s stature as a factor in his susceptibility is unclear. According to the presentence report, Parish is 5'11" and weighs 190 pounds. The reference to Parish’s stature may have been related to the way he carried himself. Perhaps the judge thought Parish looked smaller than the probation officer thought he looked, or looked physically weak. The district court may also have been relying on the opinion of Dr. Scolatti, a psychologist who worked with sex offenders in the prison system. Dr. Scolatti testified that, due to “... especially his stature_ I think he’s a prime candidate to experience a lot of grief.” To the extent that stature can be considered something more than merely physical height and weight, it is something that is better evaluated by a district judge than by an appellate panel that has never seen the defendant. There is no clear error in this determination.

Demeanor is clearly a factor in Parish’s susceptibility to abuse that is more appropriately assessed by the district court than by the appeals court. Here, the district court had the opportunity to watch Parish for several hours during the sentencing hearing. There was also considerable testimony about his demeanor, including Dr. Scolatti’s description of him as “positive and caring” and the doctor’s explanation that these are not good characteristics to have in prison. Again, we find no clear error.

As for the issue of Parish’s naivete, the district court did not explain what it meant by this term. The testimony provides clues, however. Not only does Parish not have a criminal record — a factor that is already incorporated into the sentencing calculations as criminal history — he also has no apparent history of criminal activity, other than the instant offense, or criminal associations that have not led to convictions.

Naivete could also refer to his actions in the crime itself. The fact that there is no evidence that Parish ever intentionally downloaded any pornography and did in any way organize the materials on his computer suggests that he may not have understood that he was coming into possession of these images, rather than merely viewing them. The trial judge may have been referring to an appearance and demeanor supporting naivete, subtleties that a cold record cannot display. That this naivete or lack of sophistication was such a general characteristic that it might make Parish less able to protect himself from ill-meaning inmates is a consideration within the discretion of the district court. Again, Parish’s naivete is a factual determination better made by a district court judge than by an appellate court. We decline to overturn the district court’s determination that Parish’s stature, demean- *1032 or and naivete are factors suggesting heightened susceptibility to abuse in prison.

The last factor cited by the district court as increasing Parish’s susceptibility to abuse was the nature of the offense itself, namely the possession of child pornography. We need not reach the question whether the nature of the offense by itself can justify a downward departure by heightening an individual’s susceptibility to abuse in prison. Instead, we address the question whether it is permissible for the district court to consider the nature of the offense in combination with other factors increasing the susceptibility to abuse. We conclude that it is. Such an approach allows the district court to take into account all the circumstances of the crime and the defendant and to make an appropriate individualized determination. See Koon, 518 U.S. at 112 , 116 S.Ct. 2035 (considering the combination of the defendants’ status as police officers, the notoriety of their crime, and the outrage about their crime for the purpose of determining whether they were susceptible to abuse in prison); United States v. Wilke, 156 F.3d 749, 753 (7th Cir.1998) (holding that an individualized determination is required by Koon ). 5

Here, in response to the district court’s questions, Dr. Scolatti testified that individuals convicted of sex offenses involving minors, including possessors of child pornography, came to prison with a “bad label” and were in for “a difficult time.” The likelihood of abuse by other prisoners as a result of the crime for which he was convicted, when considered with Parish’s individual characteristics, is sufficient to permit a departure for susceptibility to abuse. See, e.g., Koon, 518 U.S. at 112 , 116 S.Ct. 2035 (recognizing that “emotional outrage” about the offense could support a downward departure for susceptibility to abuse in prison) Dr. Scolatti’s opinion did not rest on the classification of the offense alone. He explained that it was the combination of the crime and Parish’s individual characteristics — his inexperience and his “positive and caring” nature — that made him susceptible to abuse.

In finding Parish to be susceptible to abuse, the district court relied on four different factors. This is not “mere membership in a class of offenders.” Cf. United States v. Kapitzke, 130 F.3d 820, 822 (8th Cir.1997). It is, instead, an individualized determination, taking into account the realities of what this particular individual is likely to face in prison. We find no error in the district court’s consideration of the nature of the offense in conjunction with the rest of the circumstances of this case. Accordingly, we affirm the downward departure for susceptibility to abuse in prison.

CONCLUSION

We find no abuse of discretion in the district court’s conclusion that Parish’s conduct was “outside the heartland” of the offense, nor do we find an abuse of discre *1033 tion in the court’s finding that Parish was highly susceptible to abuse in prison. Accordingly, we find no error in the downward departure from the Guidelines range. The sentence is

AFFIRMED.

. The concept of a “heartland” comes from the introduction to the Sentencing Guidelines:

U.S.S.G. ch. 1, pt. A(4)(b).

. The government does not argue that the split sentence fashioned by the district court was inappropriate.

. We are not persuaded by Parish’s argument that the government waived its objection to the departure or that it is barred from challenging the sentence by principles of judicial estoppel. Parish insists that the government admitted at sentencing that the facts support this departure. Considering the government's comment in context, we disagree. The government simply acknowledged the court's discretion to grant a departure based on Dr. Scolatti's testimony, but then went on to argue vigorously against its doing so. This acknowledgment was not a waiver. Rather, it was honest advocacy.

. Portions of Dr. Scolatti’s testimony described what we deemed irrelevant in Stevens . For example, Dr. Scolatti discussed whether Parish was likely to act on his fantasies, which takes the comparison beyond mere possession offenders. However, after the district court asked specifically about possessors of child pornography, the witness repeated his earlier opinion: Within that limited class of offenders, Parish's conduct was minimal.

. We recognize that some of our sister circuits have held that the nature of the offense is an impermissible factor in determining susceptibility to abuse in prison. See, e.g., Wilke, 156 F.3d at 753-54 ; United States v. Kapitzke, 130 F.3d 820, 822 (8th Cir.1997). We decline to make such a categorical holding. The Sentencing Commission set out certain limited factors, such as race and religion, that may never be considered "under any circumstances” in sentencing. Koon, 518 U.S. at 106 , 116 S.Ct. 2035 ; U.S.S.G. § 5H1. The nature of the offense and its impact on the likelihood of abuse in prison are not among the forbidden factors. See U.S.S.G. § 5H1. To add a factor to the very short list of factors the Commission decided could never be considered "would be to transgress the policy-making authority vested in the Commission.” Koon, 518 U.S. at 107 , 116 S.Ct. 2035 .