Glossary

A p-value, which stands for probability value, is a statistical measure between 0 and 1. It is used for hypothesis testing. In clinical trials it is used to give an indication of whether a result observed may be due to chance, or not.

A significance level should be set before data collection begins, and is usually set to 5% (or 0.05), although other levels may be used depending on the study.

A result is then said to be statistically significant (and allows us to reject the null hypothesis) if it has a p-value equal to or less than the significance level. This is generally written as p ‰¤ 0.05.
In calculating the p-value, we first assume that there really is no true difference between the two tested treatments,e.g. new versus standard treatment (the null hypothesis). We then calculate the likelihood (probability) that the difference we have observed is just due to chance if our supposition is true (that is, if there is really no true difference). This is the p-value.

So, the p-value is the probability to observe effects as big as those seen in the study if there was really no difference between the treatments. If p is small, the findings are unlikely to have arisen by chance and we reject the idea that there is no difference between the two treatments (we reject the null hypothesis). If p is large, the observed difference is plausibly a chance finding and we do not reject the idea that there is no difference between the treatments.

The Package Insert (formerly prescribing information) in the United States (USPI), is a document included inside the external packaging of a prescription or over-the-counter medicine to provide information for patients. In Europe, the patient information in the pack is the Package Leaflet (PL) (formerly called the Patient Information Leaflet (PIL)).

The document is subject to detailed regulatory specifications, including approved chemical and proprietary names, descriptions, and classifications clinical pharmacology

In the EU, medicinal products must be accompanied by outer and/or immediate packaging information (labelling) and a Package Leaflet (PL). The PL should be written in language understandable by the patient and must undergo readability testing. It contains:

1. What medicine X is and what it is used for (identification of the medicinal product).
   
2. What you need to know before you take/use X (contraindications and warnings and precautions for use: in children and adolescents with other medicines

A folded leaflet that comes inside the package with the medicine.

A paediatric investigation plan (PIP) is a medicines development plan to support the authorisation of a medicine for children. It aims to ensure that the necessary data is obtained through studies in children, when it is safe to do so.

Pharmaceutical companies submit proposals for PIPs to the European Medicine Agency's (EMA) Paediatric Committee (PDCO). This Committee is responsible for agreeing to or refusing the plan.

The normal development of a medicine requires that various studies be performed to ensure its quality, safety, and efficacy. In addition to this, PIPs:

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• include a description of the studies and of the measures to adapt the medicine's formulation to make its use more acceptable in children, such as the use of a liquid formulation rather than large tablets
  
• cover the needs of all age groups of children, from birth to adolescence

Paediatric Research Equity Act

Paediatric Use Marketing Authorisation

Pan American Health Organisation (PAHO) http://www.paho.org/"

An outbreak of a disease affecting a large proportion of a population and occurring over a wide geographic area.

Medicines administered via any route other than the gastrointestinal tract (oesophagus, stomach, and small and large intestines). The most frequent are subcutaneous, intravenous and intramuscular injections, but medicines that are topically administered to the eye, ear, and skin or even inhaled may be broadly considered as parenteral.