psychology definition of longitudinal design
A longitudinal design is a research study where a sample of the population is studied at intervals to examine the effects of development. In a longitudinal design, you have a group of people and you study something about them. Then you collect their contact information. After a set amount of time-be it weeks, months or years-the participants are called and asked to return. Tests are re-administered to see what changes are in the participants.
From Wikipedia, the free encyclopedia. Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of travel of the wave.rom Wikipedia, the free encyclopedia. Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of travel of the wave.