Imagine a world without longitudinal studies, without knowing the human impact on the environment....

In our discipline (computers in education) learning over two weeks and more is considered as long-term.

Friends, when I hear long term studies or longitudinal studies, I recall the one where the little children who resisted eating 1 marshmallow were rewarded with more.  And it was found that these children performed better and had good social adjustment in later years.  In birds, perhaps a long term study is over days; there may be a suitable proportion of a lifespan. (From mobile).

Hi,

I think it mainly depends on the topic of research. In animals, I would think that it mainly depends on the generation time of the targeted species, while for environmental conditions a 5-10 years study will be considered as a long-term study.

Time is a relative notion and I think you can only establish long-term definition owing to the system under study.

Hi Marcel - I believe that it's because of our study designs. Most of our studies involve one session lab so we call them short-term study. To be honest it is difficult to find enough participants for long-term studies.

It is difficult to provide exact time duration for the long-time study.  It varies with the research area and the time duration cannot be specified.  Hence, it is not a correct question.

But many so-called long-term ecological studies cost a very small fraction of what is invested in Physics, e.g. studies that searched for decades after gravity waves or tiny particles (Jim Baggott 2012. Higgs. The Invention and Discovery of the 'God Particle', Oxford University Press, or Pedro G. Ferreira 2014. The Perfect Theory. A Century of Geniuses and the Battle over General Relativity) 

It depends on the research discipline. Dear @Marcel, @Miranda will remember, I call her to remind me on a thread where I have posted an example on 6 years study! Yes, longitudinal studies are good example of long term studies!

"A longitudinal study is observational research performed over a period of years or even decades."

http://education-portal.com/academy/lesson/longitudinal-research-definition-methods-quiz.html#lesson

https://explorable.com/longitudinal-study

Dear all, the first thing that comes in my mind is toxicology: long-term exposure: chronic; short-term: acute. In a broader sense,  I think it all depends on the topic, the discipline, the time available and mostly involve research linked to an assessment or monitoring and which is done over a longer period of time (months up to years) with statistically sound basis of replicates.

Imagine a world without longitudinal studies, without knowing the human impact on the environment....

It is a very ambiguous term..

It could be 6 months to several year..

I think it is better to avoid such word in research.. Be specific..

Dear Dhara,

I fully agree, but then we can expand the list of ambiguous terminology. Perhaps you know other examples of ambiguous terminology frequently appearing in the scientific literature?  

Since 1973, the Long-Term Study on the Isle of May (IMLOTS) has grown so that today it is the most data-rich and complex study of its type in Europe. IMLOTS forms part of CEH’s network of long-term monitoring sites for detecting effects of environmental change, particularly climate change. 

http://www.ceh.ac.uk/sci_programmes/isleofmaylong-termstudy.html

Dear @Marcel, what a title of the article : Long-term research: Slow science!

It is about the world's longest-running experiments remind us that science is a marathon, not a sprint. The research time varies from 85 to 400 years! Fine examples are given!

http://www.nature.com/news/long-term-research-slow-science-1.12623

And there is meteorology! Monitoring techniques changed throughout these long-term studies

But see the remark of Christophe P. Perhaps it is a relative concept, e.g. expressed in relative differences in study periods across research teams? For instance, if 99% of the teams worked only for about 3 months on model species X, one team that worked for 3 years on model species X therefore conducted a long-term study on species X, also accepting that a 3 year study might be a short-term study in model species Y? 

Is 'long-term' a relative concept?