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Average Sentence Reductions Under Rule 35(b)
The reduction is smaller than most defendants expect, and it arrives later.
Rule 35(b) of the Federal Rules of Criminal Procedure permits a federal court to reduce a sentence after it has been imposed, but only if the defendant has provided substantial assistance to the government in investigating or prosecuting another person, and only if the government files the motion. The mechanism is narrow. The discretion belongs almost entirely to the prosecution. And the outcomes, when measured against the data the Sentencing Commission has collected, suggest that the benefit of post-sentencing cooperation is real but considerably more modest than the benefit of cooperation offered before the sentence is imposed.
This distinction matters because most defendants who cooperate after sentencing are already serving time in cases involving drug trafficking or firearms offenses, cases where the original sentences tend to be long, and where the mandatory minimum penalties constrain the floor even after a reduction is granted.
The Statutory Framework
Rule 35(b)(1) provides that the government may move for a sentence reduction within one year of sentencing if the defendant provided substantial assistance after the sentence was imposed. Rule 35(b)(2) extends that window in limited circumstances: where the information was not known to the defendant within the first year, where the information did not become useful to the government until after the deadline, or where the defendant could not have anticipated its usefulness until later and then provided it to the government without delay. The rule requires a government motion. A defendant cannot file one independently.
The Supreme Court confirmed in Wade v. United States that the government possesses, if we are being precise, a power rather than a duty to file. The circuits have applied this framing in the decades since. What the defendant provides is information. What the government provides, or withholds, is the motion itself.
What the Sentencing Commission Found
The Commission’s study of Rule 35(b) reductions across fiscal years 2009 through 2014 remains the most thorough analysis of the provision in practice. Across that period, the Commission received information on more than ten thousand Rule 35(b) reductions. By comparison, there were more than fifty-seven thousand §5K1.1 departures over the same years. The ratio tells a story the averages alone do not.
The average sentence after a Rule 35(b) reduction was eighty-three months. For defendants who received only a §5K1.1 departure at the time of original sentencing, the average was fifty-two months. In eleven offense categories, the average sentence after a Rule 35(b) reduction was at least double the average for §5K1.1 recipients. Robbery offenders with Rule 35(b) reductions averaged one hundred and two months; those receiving §5K1.1 departures averaged fifty-one.
The reduction itself, measured as a percentage decrease from the original sentence, was something in the range of thirty-seven percent. The comparable figure for §5K1.1 departures, measured against the bottom of the guideline range, was larger. Whether one measures in months or in percentage, the post-sentencing cooperator receives less.
Part of this gap reflects the population. Defendants receiving Rule 35(b) reductions were convicted of drug trafficking offenses at a rate approaching three-quarters, and were more likely to have been subject to a mandatory minimum penalty than those receiving §5K1.1 departures. These are cases where the original sentences tend toward the long end of the guidelines, and where any reduction still leaves time to be served.
The number of reductions declined over the study period, from just over two thousand in fiscal year 2009 to roughly sixteen hundred by fiscal year 2013. The overall federal caseload decreased in that window, but by a much smaller margin, though the reasons for the steeper decline in Rule 35(b) usage are not settled.
Most defendants did not receive their reduction within the first year. The largest share received it between one and two years after the original sentence. The average elapsed time was just over two years, and for defendants who also received a §5K1.1 departure, slightly longer. The data does not explain why.
The Gate the Government Controls
Only the government can file a Rule 35(b) motion, and this fact governs nearly everything that follows.
Wade v. United States established that this gatekeeping function is subject to constitutional limits. A prosecutor’s refusal to file cannot rest on an unconstitutional motive, such as race or religion. But the threshold for judicial review is steep. A defendant must make a substantial showing of improper motive; a claim that the defendant provided substantial assistance, without more, is not enough.
The Court was precise on this point.
In practice, the government’s assessment of whether assistance qualifies as “substantial” is nearly unreviewable. Prosecutors evaluate the cost and benefit of filing. If the information did not lead to an arrest, if the case fell apart, if the assistance did not move an investigation forward, the government may decline. There is no independent arbiter of that determination.
The cooperation agreement, in most cases, preserves the government’s discretion to decide whether the assistance was substantial. The defendant signs this language. It is rarely discussed in the detail it deserves.
Defendants who cooperate without a written agreement occupy a more precarious position. Verbal understandings carry no enforceable weight. A prosecutor (who, it should be noted, may have inherited the case from the AUSA who made the original representations, and who may view the defendant’s contributions through a lens shaped by a caseload the defendant knows nothing about) is not bound by what a predecessor discussed in a conference room eighteen months prior. The plea agreement is the document that governs, and if it states the government “may” file rather than “will” file, the distinction controls the outcome.
Geographic Concentration
The use of Rule 35(b) is not distributed evenly across the federal system. The Commission’s data showed that district courts within the Fourth and Eleventh Circuits accounted for nearly half of all reductions over the study period. The Eastern District of Virginia alone accounted for close to fourteen percent of all Rule 35(b) reductions. In four districts, courts used Rule 35(b) as the primary vehicle for rewarding substantial assistance in more than three-quarters of cooperation cases.
The combined D.C., First, and Second Circuits accounted for well under three percent. A defendant cooperating in one district inhabits a different procedural world than one cooperating in another, even if the offenses and the quality of assistance are comparable. Most defendants do not choose where they are prosecuted.
What Defendants Misunderstand
The most common error is temporal. Defendants assume that cooperation offered after sentencing will be credited on the same terms as cooperation offered before. The Commission’s data tells a different story. The §5K1.1 motion, filed at or before sentencing, produces a larger reduction on average, a shorter final sentence, and a benefit that is visible to the sentencing judge at the moment the original sentence is calculated. Rule 35(b) operates after the fact. The original sentence has been imposed. The guideline range has been applied. The mandatory minimum, if one exists, has already constrained the floor.
In our experience, the period between the end of active cooperation and the filing of the Rule 35(b) motion, during which the defendant has surrendered all information of value and possesses no remaining means by which to compel the government to act, is the period of greatest uncertainty and, for most clients, of greatest frustration.
There is also a misunderstanding about scope. Rule 35(b)(4) permits a court to reduce a sentence below a statutory mandatory minimum, one of the few mechanisms in federal law that can override such a floor after conviction. But the provision’s existence does not mean courts exercise it as a matter of course. The judge retains discretion. The government’s recommendation is a recommendation. The reduction may fall short of what the government proposed, and courts have declined to reduce sentences entirely even after finding that substantial assistance was provided.
We approach the timing question differently, and the reason is practical. The standard advice is to cooperate and wait. Our practice is to begin documenting the scope and impact of the assistance from the earliest moment, not because the documentation compels a filing, but because the passage of time degrades the government’s institutional memory of what the defendant contributed. Prosecutors rotate. Case agents transfer. The file that seemed complete in January looks thinner by October. A contemporaneous record, prepared by defense counsel and shared at intervals with the assigned AUSA, preserves the factual basis for the motion even when the personnel change.
Whether this approach produces measurably better outcomes is something I am less certain about than the preceding paragraph might suggest. The sample is not scientific. But the alternative, which is to cooperate and then remain silent, has produced enough poor outcomes in our practice that we no longer recommend it.
The Quiet Arithmetic
The question most clients ask is how much time they will save. The honest answer is that no formula exists, and any attorney who provides one is estimating from a dataset that is incomplete and jurisdiction-dependent.
What can be said is this: the average reduction is meaningful but not transformative. A defendant serving a ten-year sentence who receives a reduction in the range of thirty-seven percent is looking at something closer to six and a half years. That is a real difference. It is also not freedom. The defendant remains in custody, the conviction remains on the record, and the terms of supervised release govern what comes after.
For defendants subject to mandatory minimums in drug or firearms cases, the reduction brings the sentence closer to what it might have been had the defendant cooperated before sentencing. In some cases, it brings the sentence below the mandatory minimum entirely. In others, the reduction leaves the defendant above the statutory floor, with a sentence that reflects the court’s exercise of a discretion that was never guaranteed to produce a particular result.
A consultation is where this conversation begins; there is no cost for the first call, and no assumption that cooperation is the correct path.