Clinical Research and Statistics Terms

The average time that patients in a clinical study remained alive.

The section readers skip is the one that decides whether the result at the end of the paper means anything at all.

A disease or the incidence of disease within a population.

A ceiling found by pushing upward until harm appears, which suits chemotherapy and fits modern targeted drugs poorly.

A clinical trial that is carried out at more than one medical institution.

Describes a clinical trial or other experiment in which the researchers know what treatments are being given to each study subject or experimental group.

A clinical study that includes some, but not all, of the eligible patients identified by the researchers during the study registration period.

A clinical trial in which the participants are not assigned by chance to different treatment groups.

Not a ratio of risks, though it is read as one constantly, and the gap between the two widens as an outcome becomes common.

Choosing which result to measure decides what a study is able to claim, which is why the choice is fixed before anyone is enrolled.

The percentage of people in a study or treatment group who are alive for a certain period of time after they were diagnosed with or treated for a disease, such as cancer.

A filter rather than a guarantee: it tests method and reasoning, and rarely tests whether the underlying data are real.

The first time a new treatment is given to people, with safety and dose as the questions rather than whether it works.

A small rehearsal run to find out whether the real study could be done at all, not whether the treatment works.

A placebo is an inactive substance or sham treatment used in research to distinguish a therapy's true effect from expectation and natural change.

Refers to a clinical study in which the control patients receive a placebo.

The main result that is measured at the end of a study to see if a given treatment worked (e.g., the number of deaths or the difference in survival between the treatment group and the control group).

A situation or condition, or a characteristic of a patient, that can be used to estimate the chance of recovery from a disease or the chance of the disease recurring (coming back).

In medicine, a study or clinical trial in which participants are identified and then followed forward in time.

Fixing the plan in writing before anything starts is what stops a result being explained away by choices made after the fact.