The federal government has 31 separate sanctions programs, according to the U.S. Office of Foreign Assets Control (OFAC). Some of them are country-focused, while others are more thematic, dealing with nuclear nonproliferation or the diamond trade. Without question, however, the United States is more reliant on that instrument of diplomacy than ever before. It is a golden age of using economic statecraft.

Of course, there are lots of questions and risks surrounding the use of economic sanctions. A better understanding of how they work — and how the U.S. government thinks they work — is always a good thing.

So it is interesting to see the U.S. Government Accountability Office analyze these very questions. In a report released last week, the GAO tried to address two questions. The report “(1) examines the extent to which U.S. agencies assess the effectiveness of sanctions, and (2) identifies factors that have been shown by publicly available studies to contribute to the effectiveness of economic sanctions.” Full disclosure: I was one of the academics the GAO consulted as they went about their research. My contributions were limited to, “You should definitely read this study!” and “You really want to look at this paper? Ewww.”

Readers who are curious about economic sanctions but do not want to read the academic literature should check out the second half of the report. Graduate students eager for a sanctions bibliography should definitely check out the second half of the report.

For those of us who are all too familiar with the literature, however, the interesting parts are what officials from the relevant Cabinet agencies told the GAO about how they monitored the effect of sanctions. According to the report, “Treasury, State, and Commerce assess potential and observed impacts of specific sanctions, but officials stated they do not conduct agency assessments of the effectiveness of sanctions in achieving broader U.S. policy goals and cited various difficulties in doing so.” Treasury, to its credit, does appear to engage on prospective and retrospective impact assessments on sanctions programs through its Office of Terrorism and Financial Intelligence. State and Commerce have performed occasional assessments. All three departments rely on the intelligence community as well.

Most of these assessments, however, are economic: the effect of the sanctions on the target economy, or the negative spillover effects of sanctions on third parties. No one in the U.S. government appears to be assessing whether the sanctions are accomplishing their policy goals in real time.

To some outside analysts, this is problematic. The McChrystal Group’s Micah Zenko, for example, tweeted that the GAO study was “depressing” because, “US Govt officials acknowledge they cannot determine if economic sanctions work, and aren’t required to do so.”

I am not sure if this criticism is entirely fair, for a few reasons. The GAO noted official reasons for the lack of such assessments. Treasury officials said that if U.S. policy goals and objectives shift, that makes it difficult to measure sanctions’ effectiveness. OFAC officials said that with ongoing sanctions programs, “any assessments of a sanctions program’s effectiveness would necessarily be interim, not final, and the metrics used to measure effectiveness might change over the program’s duration.”

That last point is key. The effect of economic coercion is not linear. Sanctions don’t work … right up until the moment that they do work. Interim assessments run the risk of missing that rather important fact.

If I was ever appointed to be sanctions czar, I would suggest a few rough guidelines to alleviate concerns about sanctions without micromanaging them. First, sanctions designed to deny an actor’s ability to do something need to be evaluated separately from sanctions designed to coerce a change in behavior. Sanctions against narcotics traffickers, for example, are never going to “work” in the sense of stopping narcotics trafficking. That does not mean these tools are not useful, but any assessment of their utility has to be different from sanctions designed to compel.

As for the latter category, I would recommend a mandatory political assessment of any sanctions program after five years of implementation. Most successful sanctions episodes are resolved sooner rather than later. After half a decade, some stocktaking seems appropriate. Indeed, a five-year assessment offers a useful point for the United States to consider whether the sanctions should persist or a different course of action should be taken.

Props to the GAO for the report. It is asking the right questions. The sanctions community needs to think harder about offering up some answers.

Correction: An earlier version of this article incorrectly identified Micah Zenko's employer. He works for the McChrystal Group, not the Council on Foreign Relations, his previous employer.