longitudinal study

Examples of longitudinal study in the following topics:

• Inputs

  • A longitudinal study is a correlational research study that involves repeated observations of the same variables over long periods of time — often many decades.
  • It is a type of observational study.
  • Longitudinal studies are often used in psychology to study developmental trends across the life span, and in sociology to study life events throughout lifetimes or generations.
  • The reason for this is that unlike cross-sectional studies, in which different individuals with same characteristics are compared, longitudinal studies track the same people, and therefore the differences observed in those people are less likely to be the result of cultural differences across generations.
  • Because of this benefit, longitudinal studies make observing changes more accurate, and they are applied in various other fields.

• Methods for Researching Human Development

  • These include longitudinal, cross-sectional, sequential, and microgenetic designs.
  • In a longitudinal study, a researcher observes many individuals born at or around the same time (a cohort) and carries out new observations as members of the cohort age.
  • Longitudinal studies often require large amounts of time and funding, making them unfeasible in some situations.
  • Cross-sequential designs combine both longitudinal and cross-sectional design methodologies.
  • In a longitudinal study, a researcher observes many individuals born at or around the same time and observes them as they age.

• Continuity Theory

  • Maddox provided an empirical description of the continuity theory in 1968 in a chapter of the book Middle Age and Aging: A Reader in Social Psychology called "Persistence of Lifestyle among the Elderly: A Longitudinal Study of Patterns of Social Activity in Relation to Life Satisfaction. " In 1971, Atchley formally proposed the theory in his article "Retirement and Leisure Participation: Continuity or Crisis?

• Surveys

  • In a cross-sectional study, a sample (or samples) is drawn from the relevant population and studied once.
  • Such studies cannot, therefore, identify the causes of change over time necessarily.
  • A study following a longitudinal design takes measure of the same random sample at multiple time points.
  • However, longitudinal studies are both expensive and difficult to do.
  • It’s harder to find a sample that will commit to a months- or years-long study than a 15-minute interview, and participants frequently leave the study before the final assessment.

• Repeated Measures Design

  • For instance, repeated measures are collected in a longitudinal study in which change over time is assessed.
  • Other studies compare the same measure under two or more different conditions.
  • Study changes in participants' behavior over time: Repeated measures designs allow researchers to monitor how the participants change over the passage of time, both in the case of long-term situations like longitudinal studies and in the much shorter-term case of order effects.

• Fieldwork and Observation

  • For example, Sudhir Venkatesh's key informant, JT, was the leader of the street gang Venkatesh was studying.
  • Although it often involves studying ethnic or cultural minority groups, this is not always the case.
  • One of the most common methods for collecting data in an ethnographic study is first-hand engagement, known as participant observation .
  • Questionnaires can also be used to aid the discovery of local beliefs and perceptions and, in the case of longitudinal research where there is continuous long-term study of an area or site, they can act as valid instruments for measuring changes in the individuals or groups studied.
  • One of the most common methods for collecting data in an ethnographic study is first-hand engagement, known as participant observation.

• Characteristics of Sound

  • Sound is a longitudinal wave of pressure that travels through compressible medias, which can be solid, liquid, gaseous, or made of plasma.
  • Before delving too far into the physics of calculating sound waves (studying things like the Doppler Effect, for example), lets address some basics of sound.
  • Sound is a wave—a longitudinal wave of pressure that travels through compressible medias (i.e., solid, liquid, gaseous, or made of plasma).
  • Sound travels in longitudinal waves.

• Longitudinal Waves

  • An example of a longitudinal wave is a sound wave.
  • Some longitudinal waves are also called compressional waves or compression waves.
  • Like transverse waves, longitudinal waves do not displace mass.
  • Longitudinal waves can sometimes also be conceptualized as pressure waves.
  • A compressed Slinky is an example of a longitudinal wave.

• Longitudinal and Transverse Waves

  • Sound waves are longitudinal waves.
  • As it comes from behind you, a transverse waves lifts you up and then drops down; a longitudinal wave coming from behind pushes you forward and pulls you back.
  • single particles being disturbed by a transverse wave or by a longitudinal wave (http://cnx.org/content/m13246/latest/Pulses.swf);
  • (There were also some nice animations of longitudinal waves available as of this writing at Musemath. )
  • The "highs and lows" of sound waves and other longitudinal waves are arranged in the "forward" direction.

• Muscularis

  • The muscularis externa consists of an inner circular layer and a longitudinal outer muscular layer.
  • The circular muscle layer prevents food from traveling backward and the longitudinal layer shortens the tract.
  • The layers are not truly longitudinal or circular, rather the layers of muscle are helical with different pitches.
  • The inner circular is helical with a steep pitch and the outer longitudinal is helical with a much shallower pitch.
  • The outer longitudinal layer of the colon thins out into three discontinuous longitudinal bands known as tiniae coli (bands of the colon).