How we think about our impact

At ClusterFree, we work to reduce the hundreds of millions of cluster headache attacks happening every year around the world. How many attacks are we helping prevent, and at what cost? This page explains how we think about that question, so that donors can understand the impact of their donations.

Before diving into metrics and statistics, it’s worth reminding ourselves of what’s at stake.

A severe cluster headache attack is, put plainly, torture. The pain belongs in a category of its own, and while comparisons to other types of pain can help, the only way to truly understand the pain is to experience it firsthand. If you have not, imagine undergoing invasive eye surgery (the eye is very richly innervated by the trigeminal nerve) without anesthesia. How much should we be willing to pay, and how much do we expect governments to pay, to prevent the most excruciating experience of our lives?

Luckily for most of us, anesthesia is standard of care: in the US alone, 40 million anesthetics are administered every year, and over 60,000 patients per day receive general anesthesia. Denying a patient anesthesia for surgery would be scandalous and deeply immoral. Yet this is the reality for many cluster headache sufferers who cannot get proper pain relief, perhaps because their insurance refuses to cover high-flow oxygen, because governments fail to invest in cluster headache research, or because governments have made a whole class of effective treatments illegal.

How, then, do we quantify the impact of our work? Returning to the example of surgery without anesthesia: even if the procedure carried zero risk of death or long-term disability, we would still do almost anything to avoid it. Yet one hour of excruciating suffering, followed by a pain-free and disability-free life, registers as a rounding error in standard health metrics, such as the QALY, DALY, and WELLBY. This, we argue, is a catastrophic oversight and a failure of our healthcare systems, and it calls for a metric built for suffering, not just for health.

Recognizing this, Jonathan Leighton of the Organisation for the Prevention of Intense Suffering has suggested a new metric: the “Day Lived in Extreme Suffering” (DLES), defined as a day spent in “the most urgent suffering at the level of approximately 9/10 and above.” Conveniently, cluster headache patients who track their attacks typically use a 1–10 pain scale.^[1] One DLES could thus be operationalized as, for example, 24 attacks rated ≥9/10 and lasting one hour each.

We have estimated that cluster headache patients spend about 3.1 million days per year at ≥9/10 pain—3.1 million DLES. We want to bring that number down as far as we can.

Our theory of change describes the various ways to meaningfully reduce the burden of cluster headache, and the goals we have chosen to focus on given our current resources and comparative advantages. Here, we illustrate how we quantify our impact in dollars per DLES averted, using one of our initiatives as an example: ClusterInfo.org, a website hosting high-quality, multilingual guides on how to treat^[2] cluster headache. By distributing these guides as widely as we can, we hope to help many patients quickly find treatments that work, preventing attacks that would otherwise have happened. This dashboard shows some of the web analytics we track as proxies for how many patients we’re reaching. In addition, visitors can tell us directly how the guides helped them through our survey.

Our model estimates how many attacks (or how much time in pain) we can prevent with a given budget, under assumptions about the number of patients our guides help and the counterfactual relief they get (fewer, shorter, or less intense attacks). Because ClusterInfo only launched in late May 2026, we don’t yet have enough data (as of mid-July 2026) to estimate our counterfactual impact precisely. But the orders of magnitude are illustrative, and we will publish updated numbers as more data comes in.

For instance, with an annual budget of $50,000, and assuming ClusterInfo reaches 10,000 unique visitors, a donation to ClusterFree would achieve the following:

• $488 would avert one DLES (80% range: $222–$1,459)
• $3 would avert one cluster headache attack on average across all pain levels ($1–$8), or $4 per attack-hour
• $17 would avert one severe attack at ≥9/10 pain ($8–$50), or $20 per attack-hour

Since ClusterFree is currently the only organization measuring cost-effectiveness in dollars per DLES averted, no benchmarks exist for this metric. But we believe that preventing 24 hour-long episodes of excruciating pain for about $500 is an attractive option for donors who care about reducing intense suffering. For comparison, in the US, one QALY is valued at around $100,000–$150,000 (and the most cost-effective global-health charities are estimated to save a life for roughly $3,000–$5,500). $100,000 per QALY implies valuing an hour of healthy life at $11. Conservatively, we estimate that migraine patients would be willing to pay $5 to replace an hour of severe migraine with a healthy hour, so a patient should be willing to pay more to avert an hour of cluster headache pain. Averting an hour of cluster headache pain for $4 (or extremely severe pain for $20) would therefore be very competitive.

Once calibrated with real-world data, our cost-effectiveness model will likely give a lower bound of ClusterInfo’s impact, because it only counts patients directly helped by our guides. It ignores, for example, doctors who read our guides and go on to treat many patients, or patients who spread the word about effective treatments without sharing the guides themselves, among others.

ClusterInfo is only one of several projects we’re pursuing, so the model also includes a simplified calculation of ClusterFree’s overall cost-effectiveness, based on how many patients we can help per year and the counterfactual relief they get from our work. This includes, for example, patients who learn about effective treatments on the ClusterFree website after signing one of our open letters or watching our videos. We are also supporting research efforts to bring new, effective treatments to market: a longer-term bet, but one with high expected upside.

And while our metrics focus on time in severe pain, our work may have benefits we’re not measuring. For instance, many patients suffer from mental health conditions, including depression, anxiety, or (complex) PTSD, which can improve once they find treatments that work.

ClusterFree launched in November 2025, and at this early stage we’re still exploring several paths to impact. Ideally, we’d focus on a single, highly scalable intervention. ClusterInfo.org might be it, especially if we also manage to capture the hundreds of thousands of sufferers who don’t yet know what they have but are desperately looking for help. We are working on guides targeted at them, but we’re currently limited by how much research and translation work our team can take on, even with the help of LLMs.

If you want to play a part in making cluster headaches a thing of the past, consider donating, or get in touch to get involved.