Dear RG community,
I found it a bit confusing on few terms and aspect of study design.
1. From my understanding, longitudinal study is an observational study consist of cohort (prospective or retrospective) and panel study.
How about diary study, is it considered panel study?
How about repeated cross sectional studies that also often referred as longitudinal study?
2. Experimental study consist of before-after (or known as pre-post) or repeated measure interventional study, either randomized or non-randomized. Am i right?
3. For longitudinal study, especially prospective cohort, most references highlight on two group (exposed vs unexposed) with similar baseline and categorical outcome measure.
How about single group cohort with different baseline and outcome continous measure?
4. For longitudinal study especially cohort study, most references talk about months to years of followup duration.
But, for some psychlogical measure such as stress and fatigue, there should be no problem to conduct shorter duration of cohort study e.g. within 8 hours, am i right? For example, we measure baseline stress level prework, and followup the outcome stress messure postwork, i.e. after 8 hours of continous work. Is it appropriate?
.
Thank you for kind assistance.
Your response is highly appreciated.
Regards,
Fadhli
Mohd Fadhli - In longitudinal study the data is gathered for the same subjects repeatedly over a period of time and it can extend over years or even decades. A cohort study can be studied over a time limit but the cohorts can remain at one period of time. Cohort studies are used to study incidence, causes, and prognosis. Panel is group of respondents recruited to take part in a number of research sessions or projects over a period of time. Many panels are quantitative in orientation, but some qualitative panels exist. Panel studies are a particular design of longitudinal study in which the unit of analysis is followed at specified intervals over a long period, often many years. The key feature of panel studies is that they collect repeated measures from the same sample at different points in time A diary study is a research method used to collect qualitative data about user behaviors, activities, and experiences over time. In a diary study, data is self-reported by participants longitudinally — that is, over an extended period of time that can range from a few days to even a month or longer. “Before” refers to a measurement being made before an intervention is introduced to a group and “after” refers to a measurement being made after its introduction. A"pre-post"study examines whether participants in an intervention improve or regress during the course of the intervention, and then attributes any such improvement or regression to the intervention.
Mohd Fadhli - In longitudinal study the data is gathered for the same subjects repeatedly over a period of time and it can extend over years or even decades. A cohort study can be studied over a time limit but the cohorts can remain at one period of time. Cohort studies are used to study incidence, causes, and prognosis. Panel is group of respondents recruited to take part in a number of research sessions or projects over a period of time. Many panels are quantitative in orientation, but some qualitative panels exist. Panel studies are a particular design of longitudinal study in which the unit of analysis is followed at specified intervals over a long period, often many years. The key feature of panel studies is that they collect repeated measures from the same sample at different points in time A diary study is a research method used to collect qualitative data about user behaviors, activities, and experiences over time. In a diary study, data is self-reported by participants longitudinally — that is, over an extended period of time that can range from a few days to even a month or longer. “Before” refers to a measurement being made before an intervention is introduced to a group and “after” refers to a measurement being made after its introduction. A"pre-post"study examines whether participants in an intervention improve or regress during the course of the intervention, and then attributes any such improvement or regression to the intervention.
Dear @Dr Manzoor Hussain
Thank you for your valuable input.
Let me copy your input separately:
==========
1. Longitudinal Study
Longitudinal study the data is gathered for the same subjects repeatedly over a period of time and it can extend over years or even decades.
2. Cohort Study
A cohort study can be studied over a time limit but the cohorts can remain at one period of time. Cohort studies are used to study incidence, causes, and prognosis.
3. Panel
Panel is group of respondents recruited to take part in a number of research sessions or projects over a period of time. Many panels are quantitative in orientation, but some qualitative panels exist.
4. Panel studies
Panel studies are a particular design of longitudinal study in which the unit of analysis is followed at specified intervals over a long period, often many years. The key feature of panel studies is that they collect repeated measures from the same sample at different points in time.
5. Diary Study
A diary study is a research method used to collect qualitative data about user behaviors, activities, and experiences over time. In a diary study, data is self-reported by participants longitudinally — that is, over an extended period of time that can range from a few days to even a month or longer.
6 Before-After Study
“Before” refers to a measurement being made before an intervention is introduced to a group and “after” refers to a measurement being made after its introduction.
7. Pre-post Study
A"pre-post"study examines whether participants in an intervention improve or regress during the course of the intervention, and then attributes any such improvement or regression to the intervention.
====================
I would like to clarify few things based on your input:
a) The key different between cohort and panel is that the group of people is the same in panel over period of time, but they may be different group of people in each time period for cohort.
b) Cohort study seems like a repeated cross sectional study over different group of people, but panel study is repeated measures over same group of people.
c) For diary study, if researcher collect quantitative data instead of qualitative data, the design should be named as panel study.
d) I still cannot see the distinction between 'before-after' and 'pre-post'. Both refers to interventional study, but what is the key difference between them?
Thank you for taking your time in assisting me.
Regards,
Fadhli
The key difference is to ask what you are repeatedly measuring :
1) repeated cross section is different people over time (some gross unit may be being measured- eg the country), this will give you general trends but not individual volatity , so smoking has declined in general but this tells you nothing about individuals who have given up and the started agin; stocks but not flows.
2) the other designs it is the same unit that is repeatedly measured. Eg individuals on a daily basis a diary, an annual panel are measured every year. Indeed a long panel may be analysed to see cohort effects. This gives the general trend and volatility but can be very expensive and take a long time.
See this website for different types of structure, the key point in the others designs is to model overtime dependency.
http://www.bristol.ac.uk/cmm/learning/multilevel-models/data-structures.html
http://www.bristol.ac.uk/cmm/software/mlwin/mlwin-resources.html#mlmbkgrd
this stuff is actually quite hard in theory, data collection and preparation and analysis. Find a similar study and see what they have done, see this interactive web site, and then think of following it
http://www.bristol.ac.uk/cmm/gallery
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