Some journals in economics and political science have responded to that problem by requiring that authors inform the readers about where the complete set of data is available and how to obtain it. More informally, scientists make personal contact by phone or email to obtain additional data, or they visit each others' laboratories. There are no rules for such requests or visits, but it's generally understood that it's okay to ask for data that are necessary for complete understanding of a published paper and not okay to ask for data that are still being examined before publication. Good science requires that observations and analyses be repeatable and repeated. Given information about technique and procedure by the scientist who made the observation or analysis, other competent scientists should be able to replicate the observation or analysis.
Reproducibility distinguishes science from another human activity called magic.
Now, we know that magic is tricks, and that the tricks are necessarily kept secret so that non-magicians can't learn them. Science, on the contrary, works best when it's open to skepticism, review, and attempts at replication. I am going to focus on scientific data are used for the development of laws, rules, and regulations, risk assessments and other government guidance documents, and I am going to divide those data into two types. Laboratory experiments and replication of laboratory data can be attempted in other laboratories. Most everyone can remember about a decade ago, when cold fusion burst into the news.