1. What kind of source is behind it?
A survey describes responses from a population; a test examines controlled conditions; a rule establishes obligations. They do not answer the same question. Begin by finding the original document and recognising its nature. A press release can explain research well, but should lead to the work it summarises, with its method and limitations.
The appearance of authority does not identify the document either. An official PDF may be a draft, and a university webpage may be a press release. Knowing what you are reading lets you ask for the kind of answer it can actually provide.
2. Who or what was studied?
The CDC and FDA report on the 2024 US National Youth Tobacco Survey concerns students at particular school levels in the United States. Its results are not figures for Spain or the entire adult population. This example shows why country, age, sample selection and time period should travel with a statistic when it is shared.
In a laboratory study, the same question concerns the devices and samples. A result obtained with several particular models should not automatically be extended to all products sharing a generic commercial name.
3. What exactly does the measure mean?
The cited survey defines current use by reference to the previous thirty days. That category does not necessarily mean daily use. If a news story removes the definition, two sentences can look equivalent while describing different behaviours. Methodological notes often contain these distinctions that a headline cannot develop.
Also look at the denominator. A percentage among people already using a product is not a percentage of the whole population. Before repeating a figure, finish the sentence: a percentage of whom and over which period?
4. Does the comparison support the headline?
A study may compare concentrations of a substance under particular conditions. That does not automatically amount to an overall comparison of every health risk. Similarly, an association observed in a survey does not establish a causal relationship on its own. Retaining the original question helps reveal when a news story has expanded the answer too far.
Also look for the uncertainty the authors explain and the alternatives they consider. Limitations are not a decorative clause at the end: they indicate where the work’s support for a conclusion ends.
5. What is needed for the next step?
Replication, follow-up, another assessment or publication of a rule may still be needed. Identifying that step prevents a preliminary result from becoming a personal recommendation or an announcement from becoming a current obligation. It is also worth checking funding and disclosed conflicts without using them as substitutes for examining the method.
The WHO warns about risks associated with electronic cigarettes and their emissions. Reading studies critically does not mean ignoring those warnings: it means communicating evidence precisely. A news story improves when it explains what is known, retains its limits and lets readers open the source.
Take this with you
Identify the source, population, measure, comparison and next step before turning a headline into a conclusion.
Sources you can open
The source may be in its original language. English publication does not change the jurisdiction or date discussed.
Follow the thread
Open the cannabinoid encyclopedia
Check the identity, research, uncertainties and documented forms of each compound.