Which research design uses participants of different ages at one point in time?

Development primarily refers to changes that occur over the first part of the lifespan, which are often thought of as positive, unidirectional, and cumulative. Development is often used to describe advances in such areas as motor skills, language, and cognition.

Maturation refers to growth and other changes in the body and brain that are associated with underlying genetic information. Therefore, maturation is considered to be relatively automatic and development encompasses both maturation and an individual’s life experience.

Aging refers to changes associated over the latter part of the lifespan and is often linked with loss of function in the areas of motor skills, language, and cognition.

Change over time is a more general way to capture temporal changes that is predominantly due to learning and experience. Scientists debate how to define these terms, but learning is often restricted to changes tied to specific instruction or experiences over relatively short periods of time whereas development and aging are thought to be universal processes impacting all members of a species.

Designs to Study Change Over Age and Time
There are a number of designs that allow researchers to understand causes of differences between individuals of various age groups, or within the same individual over time. Four approaches to developmental research discussed in the textbook are: cross-sectional, longitudinal, cross-sequential, and microgenetic.

Cross-sectional Designs
Cross-sectional research designs are the most common types of studies across age and time. They involve simultaneously assessing two or more different age groups. One challenge is determining the spacing between ages (how wide the gap in days, weeks, months, or even years) and results from past research, theoretical arguments, and your research question should all inform that decision.

Advantages of Cross-Sectional Designs
A main advantage of a cross-sectional design is that it allows researchers to gather information about different age groups in a short period of time. They also offer great ways to discover and document age-related differences associated with certain behaviors.

Disadvantages of Cross-Sectional Designs
Cross-sectional designs do not identify the underlying causes of differences across age groups. Researchers cannot tell whether age, maturation, specific learning experiences, or a combination of the above are the root of the difference. It is also possible that a cohort effect, the result of experiences that impact an entire group of individuals, is at play.

A second limitation of a cross-sectional design is verifying that methods are equally good at measuring behaviors for different age groups in the sample, which is known as having equivalent measures.

Lastly, cross-sectional designs tend to underestimate variability within an age group in order to characterize differences between groups. Because the focus is on differences between ages, it is possible that achievements obtained at specific ages gain greater status than they deserve.

Longitudinal Research Designs
Longitudinal research designs tracks groups of participants over a period of time with two or more assessments of the same individuals at different times. These designs can last any amount of time. Short-term designs tend to be used for infants. Most longitudinal designs are conducted over longer periods of times, often for several months, years, or even decades.

Advantages of Longitudinal Research Designs
One advantage is that longitudinal designs can help researchers understand how processes change in individuals. Another advantage is that these designs generate a lot of data and can allow researchers to explore a wide variety of research questions.

Disadvantages of Longitudinal Research Designs
The main challenge of using a longitudinal design is the cost in time and resources. These studies are much more expensive and take much longer to conduct than a cross-sectional study with the same number of participants.

A second issue is the impact of repeated testing. Much like a within-subjects design, researchers need to assess participants several times in a longitudinal study and this might influence participants.

The third limitation of longitudinal research is that it faces subject attrition. Subject attrition poses two issues: 1. It might lead to insufficient number of participants at the end of the study, which may mean not having enough statistical power. 2. It may result in significant changes to the study over the course of multiple assessments in terms of biases in who drops out. There are methods of minimizing attrition such as providing incentives, although these issues related to participant retention are ones that local IRBs will want to know about.

A fourth disadvantage of longitudinal studies is maintaining research personnel over time. In cases where studies last many years, staff might need to be changed and it is critical that the protocol is kept consistent.

A fifth disadvantage is determining whether the outcomes observed are due to developmental processes or to the timing of data collection that impacted all the participants.

Finally, the quality of a longitudinal study depends greatly on the initial sample and the quality of the measures in the earliest assessments. While these are factors critical to all studies, researchers using a longitudinal design have a much more difficult time recruiting a new sample in the middle of their study.

Which research design uses data with people of different ages collected a single point in time?

Which research design that the individuals of different ages are compared at one time?

What design is used in a study which has different participants of the same ages at different historical time points?

What research design that collects data at one point in time?