Terms starting with M

Manual of Procedures

The manual of procedures is a set of procedures describing how to conduct a clinical study. It was developed to create consistency in how studies are designed, and run and how information is collected across various clinical study populations and clinical sites.


Masking in clinical studies is when participants or investigators (or both) are unaware of who is receiving treatment and who is not receiving treatment. This is done to reduce bias.

Master Protocol

A master protocol is a single clinical study design that can be used to test multiple medicines and/or multiple groups of participants. This negates the need to develop multiple designs for multiple clinical studies.

Matched-pair Design

Matched-pair design is a type of clinical study design in which investigators identify a pair of participants who are 'identical' with respect to relevant factors. Then investigators administer different treatments to each of these pairs to see how a treatment affects participants with similar characteristics.


The mean is when you take a number of different measurements of the same thing, add them all together and then then divide by the number of measurements to get an average. Let's say you take your temperature three times, and it is 97, 98 and 99 degrees F consecutively. Add them together and you get 294. Divide by three (the number of readings) and you get 98. That is your mean.

Medical Countermeasures

Medical countermeasures are medicines (such as vaccines, antimicrobials, and antitoxins) and other products (such as ventilators, diagnostic tests, personal protective equipment, and decontamination materials) that may be used to prevent, mitigate, or treat the adverse health effects from a public health emergency. (CDISC)

Medical Device

A medical device is any instrument, apparatus, implement, machine, appliance, implant, software, or other similar or related article, intended by the manufacturer to be used for human beings (alone or in combination) for one or more specific medical purpose(s). (CDISC)

Medication Error

Medication error is any unintentional error in the prescribing, dispensing, or administration of a medication.

Mega Trials

Mega trials are massive large-sample clinical studies that test the advantages of therapeutic interventions by enrolling 10,000 or more participants. (CDISC)


Meta-analysis is the formal evaluation of information collected from two or more different clinical studies examining the same question, treatment, medicine, etc.


Metabolism is how the body biochemically breaks down and transforms what we consume into various substances that our body can more easily and readily use for its various vital functions.


Metadata is the information (data) that describes other information (data). For example, with a book, the words in the book are the data. However, the author, the publisher, the date it was published, and the number of pages are metadata, because they describe the main data — the content of the book.

Missing Data

Missing data is information collected in a clinical study that is incomplete or corrupted. This can happen for a number of reasons: difficulties in assessing outcomes, lack of adherence to clinical study protocol, poor response to participant queries, etc.


A model is the general design of clinical study regarding the strategy for assigning interventions to participants or groups of participants and the analysis of data.

Morbidity Rate

The morbidity rate is the frequency that a specific illness occurs in a defined population during a specified time interval.

Mortality Rate

The mortality rate is the frequency that death occurs in a defined population during a specified time interval.

Multicenter Trial

A multicenter trial uses exactly the same methods at more than one site. It is therefore usually directed by more than one investigator.