Statistics How To

Randomized Clinical Trials > You may want to read this article first: What is a Primary Endpoint? What is a Composite Endpoint? A composite endpoint is an endpoint that is a combination of multiple clinical endpoints. Composite endpoints can be primary or secondary: Primary composite endpoints are the main measurements for a trial; They answer … Read more

Randomized Clinical Trials > What are Historical Controls? A historical control is where old data is used to compare with new data from new trials. Information is essentially “borrowed” from historical data. The old data is usually from patients with the same disorder and might come from a variety of sources, including: Older clinical trials, … Read more

Randomized Clinical Trials > What is a Non Interventional Study? In general, a non interventional study (NIS) (also called a non interventional trial) is where a patient takes regular medicine, prescribed according to the label. In an NIS, the researcher sets out to exert as little influence as possible on the patient’s condition while studying … Read more

Experimental Design > Cross Sequential Design Cross sequential design (sometimes called a cross-sectional sequence) is a mix between cross sectional research and longitudinal research. The design begins as a cross sectional design; data is collected at one specific point in time on two or more groups. A follow up is conducted on the groups two … Read more

Experimental Design > A group sequential design is a type of adaptive design where the number of patients isn’t set in advance. Patients are divided into an equal number of groups and data is analyzed at pre-determined points in the trial. A stopping rule specifies when and why a trial might be halted at these … Read more

Hypothesis Testing > Sig(2-Tailed) You may want to read this other article first: One Tailed Test or Two in Hypothesis Testing. How to Decide. Sig and Sig(2-Tailed) in Output Output from some statistical software spits out Sig(2-Tailed) as part of the results for t-tests and correlations. Generally speaking, the “Sig” or “Sig(2-Tailed) is your p-value. … Read more

Design of Experiments > Parallel Design What is a Parallel Design? A parallel design, also called a parallel group study, compares two or more treatments. Participants are randomly assigned to either group, treatments are administered, and then the results are compared. It is the “gold standard” for phase 3 clinical trials(1). A key element of … Read more

Design of Experiments > What is a Stepped Wedge Design? The stepped wedge design is a sub-type of a randomized controlled trial, where individuals or groups are studied at different times. At the end of the trial, all participants will have received the intervention being studied, although the order in which they receive it is … Read more

Statistics Definitions > Random Seed Contents: What is a Random Seed? Random Number Generator in Excel. What is a Random Seed? A random seed specifies the start point when a computer generates a random number sequence. This can be any number, but it usually comes from seconds on a computer system’s clock (Henkemans & Lee, … Read more

Statistics Definitions > What is a Greedy Algorithm? The greedy algorithm is one of the simplest algorithms to implement: take the closest/nearest/most optimal option, and repeat. It always chooses which element of a set seems to be the best at the moment. It never changes its mind at a later point. Greedy algorithms are “top-down”, … Read more