The Wrong Question About Vaping

Ecological momentary assessment is an impressive research method because, instead of asking participants to reconstruct their behaviour days or weeks later, researchers contact them in real time to ask what they are doing, where they are, how they are feeling and what happened immediately before they vaped.

That is a genuine strength of the study under discussion. The method reduces recall bias and provides a detailed picture of vaping as it occurs in everyday life, making it valuable for behavioural science. But a sophisticated method does not compensate for asking an incomplete public health question.

The study may help us understand the moments in which people vape, but it does not establish whether those moments represent harm, benefit or some combination of the two. That distinction is not incidental; it is the central issue.

Consider two people reaching for a vape. The first is a long-term smoker who would otherwise have lit a cigarette, while the second is a young adult who has never smoked and has recently started using nicotine. The visible behaviour is the same, but its public health meaning is entirely different.

For the smoker, the episode may represent the displacement of a substantially more dangerous behaviour. For the never-smoker, it may represent a new exposure to nicotine and the beginning of dependence.

An ecological momentary assessment can record where these episodes happened, who was present, what mood the person was in and how strong the urge felt. Unless the analysis connects those episodes to smoking history and concurrent cigarette use, however, it cannot reliably distinguish substitution from initiation.

The missing counterfactual is what the person would have done if the vape had not been available. Would they have smoked a cigarette, delayed smoking, used nicotine replacement therapy or used nothing? Without that information, the significance of a vaping event remains uncertain.

Counting vaping episodes without examining their relationship to smoking is rather like counting doses of methadone without asking whether heroin use declined. The behaviour cannot be interpreted properly without knowing what it replaced—or failed to replace.

In vaping research, smoking history should not be treated as merely another variable to place in a baseline characteristics table because it is essential to interpretation. At minimum, participants should be clearly differentiated as current smokers, former smokers, dual users and never-smokers.

Even these categories are only a beginning. Among dual users, researchers should ask whether cigarette consumption is declining, stable or increasing. Among former smokers, they should examine whether vaping is associated with continued abstinence or possible relapse. Among never-smokers, they should monitor dependence, persistence and any subsequent transition to smoking.

Most importantly, studies of momentary vaping behaviour should investigate moments of cigarette forgoing: occasions when a participant wanted to smoke and had the opportunity to do so but used a vape instead. Without that context, an increase in vaping could be presented as a worsening outcome even when it accompanies a substantial reduction in smoking. Conversely, a reduction in vaping could be celebrated even if some participants returned to cigarettes.

That is what happens when the surrogate behaviour becomes more important than the health outcome.

Ecological momentary assessment is exceptionally useful for identifying patterns. It can show that vaping commonly occurs in particular social settings, during periods of stress, after alcohol consumption or alongside certain emotions. These associations may generate useful hypotheses, help researchers design behavioural interventions and reveal how nicotine use is embedded in daily routines.

What EMA cannot do on its own is establish causation. If stress and vaping occur together, the data cannot necessarily tell us whether stress caused the vaping, whether nicotine withdrawal contributed to the stress or whether a third factor influenced both. Nor can a short observational window determine whether vaping will ultimately improve or worsen a participant’s health.

This matters because descriptive findings often acquire a more dramatic life after publication. An association becomes a “risk factor,” a frequently reported context becomes evidence of a social problem, and the mere persistence of vaping is treated as failure.

Persistence, however, is not by itself a clinical outcome. A former smoker who continues vaping has not achieved nicotine abstinence, but that does not mean the person has received no health benefit. If vaping is preventing a return to combustible cigarettes, continued use may represent an imperfect but important form of harm reduction.

None of this makes vaping harmless; it means that “not harmless” and “as harmful as smoking” are profoundly different propositions.

Cigarettes are extraordinarily dangerous not simply because they contain nicotine, but because they burn tobacco and generate smoke containing a vast mixture of toxic substances. Vapes are not clean-air devices: their aerosols can contain harmful chemicals, and their long-term effects require continued study. Young people and people who have never smoked should not be encouraged to begin vaping.

Acknowledging those facts does not erase the difference between combustion and non-combustion. The relevant comparison for a smoker is not vaping versus breathing pristine mountain air; it is often vaping versus continuing to smoke.

That comparison has direct clinical importance. The 2025 Cochrane living systematic review found high-certainty evidence that nicotine e-cigarettes increased smoking quit rates compared with nicotine replacement therapy. It estimated roughly four additional quitters per 100 people treated while also stressing that longer and larger studies are needed to evaluate safety fully. The review concerned regulated nicotine products and should not be generalised to illicit or THC-containing products. (Cochrane review)

These qualifications matter, but so does the central finding. If vaping can help some people stop smoking, then research that examines vaping while pushing cigarette displacement to the margins risks missing its most consequential effect.

Vaping attracts attention partly because it is visible, novel and politically contentious. Smoking, by contrast, is familiar, and although its catastrophic health effects have been documented for decades, that familiarity can make them fade into the background even as combustible tobacco remains the dominant source of tobacco-related disease.

This creates a peculiar research imbalance. We become increasingly precise about the time of day people vape, their surroundings, their emotional state and the company they keep. We produce intricate classifications of vaping behaviour and identify its triggers, rituals and social patterns, yet the most basic outcome can remain unresolved: are fewer cigarettes being smoked?

That is not an argument against behavioural research; it is an argument for placing behavioural findings within a hierarchy of clinical importance. The frequency of vaping, nicotine dependence, youth uptake, respiratory symptoms and toxicant exposure all matter, but smoking cessation, smoking relapse and combustible-cigarette consumption matter more because they are more directly connected to the largest established burden of disease.

A study can therefore be methodologically excellent and still be clinically incomplete.

The limitations become particularly important when descriptive research is used to support regulation. Finding that people vape when stressed does not establish that restricting access to vaping will improve their health, just as finding that vaping occurs in social settings does not tell us whether a prohibition will reduce nicotine use, drive people towards unregulated products or push some users back to cigarettes.

Policy requires evidence about consequences, not merely observations about behaviour.

Before EMA findings are used to justify restrictive measures, researchers and policymakers should ask whether vaping replaced smoking, whether cigarette consumption changed, whether former smokers remained abstinent, whether never-smokers began using nicotine and whether dual use represented a transition, a stable pattern or a failed quit attempt. They should also ask what happened after the observation period and what unintended effects might follow from the proposed policy response.

These questions do not guarantee that vaping will emerge as beneficial, and in some populations it clearly may not. The point is that its public health value—or harm—cannot be inferred from the existence or frequency of vaping alone.

The goal of tobacco control should not be to make every nicotine-use graph decline regardless of what happens to smoking; it should be to reduce disease and premature death.

That means preventing nicotine uptake among people who do not use it, especially young people, and helping smokers quit all tobacco and nicotine where possible. It also means recognising that smokers who cannot or will not immediately achieve complete abstinence may benefit from moving away from combustion.

These objectives require a more discriminating framework than “vaping up, bad; vaping down, good.”

The new study contributes useful information about lived behaviour, and the researchers deserve credit for using EMA to capture the texture of everyday vaping. But detail should not be mistaken for significance.

We can know exactly when someone vaped, where they stood, who was beside them and what they felt in that moment while still not knowing whether the episode moved them towards greater or lesser risk.

Until vaping research consistently connects behaviour with smoking status, cigarette displacement and meaningful health outcomes, it will continue producing increasingly sophisticated answers to a secondary question.

The most important question remains much simpler: did the person smoke fewer cigarettes—or stop smoking altogether?

If the research cannot answer that, it should be interpreted with considerable restraint and certainly should not be treated as a sufficient basis for policies that may make movement away from combustible tobacco more difficult.