Acquisti noted the difficulty of researching "opaque blackbox" ad exchanges that aren't at all incentivized to be transparent about what's going on.
Due to the difficulty of researching this group within a clinical environment (e.g. lack of private spaces and frequent interruptions), participants were interviewed on more than one occasion over the course of their treatment.
One of the difficulties of research in osteopathic medicine where there are only a small number of intervention trials is the lack of consistency in the methodology used.
One of the difficulties of research in this area is that a proportion of eligible participants refuse to provide informed consent.
One of the difficulties of research on haustoria in Orobanchaceae is that preserved tissues are often darkly stained, which requires clearing prior to experimentation.
The obstacles mentioned were lack of money, attitudes towards research, the lack of ownership, the lack of early involvement by policymakers, the difficulties of research communication and the lack of tradition in lobbying.
Qualitative data analysed in this study, and also in the study of Oliver et al. [ 41] supports the quantitative findings on the difficulties of research participants to identify risks associated with the biobank research.
The widespread informal use of mobile technology in medical education and the difficulties of researching formal use make it hard to assess benefits to learning and training.
Regional conflicts and political instability, lack of funding, as well as the difficulty of publishing research of local interest in high impact journals were reported as major barriers for the production of research in the region [ 13, 19, 20, 35, 36].
Lack of freedom, democracy and funding, as well as brain drain and the difficulty of publishing research of local interest in high impact journals, all contribute to the low performance of biomedical research in the Arab world [ 10, 11].
The study has a variety of limitations, they said, some because of the difficulty of doing research in the dude-I-slept-through-class world of the freshman year of college, and others because of the study's design.
