Observational studies are fully naturalistic and they have, in spite of concerns on internal validity, a high external validity.
"The reason for this urgent e-mail concerns breakdowns of internal controls and resulting significant but possibly unrecognized financial losses existing within our organization," Mr. Bowen wrote.
In conclusion, temozolomide is effective in experimental glioma models, although this is qualified by concerns of the internal validity (randomisation, blinding) and of publication bias.
The lack of controlling for the factors used to match the cases and controls, as well as the small sample size, raised concerns of the internal validity of the study.
In the part concerning measurements of internal forces in prestressed elements, the strain gauge measurement, frequency measurement and measurements using instrumentation for cable and rod elements are described in details.
Some other veterans who were there have said they do not recall Mr. Kerry being present when the proposal was voted on, and the heavily edited F.B.I. files released here appear to make no direct mention of the assassination idea, except to note reports of "drastically increased militant posture of V.V.A.W. of considerable concern to internal security interests of U.S".
Policy members again cited the usual concerns: a lack of internal investment and political tensions in Ukraine and the Middle East.
Insight, on the other hand, concerns the state of internal understanding one has about one's thoughts, sentiments and behaviors [33].
The first generalization concerns the exchange of internal energy over (finite) distance, i.e., by radiation and absorption, making a weakly non-local ansatz inappropriate.
Another concern of an internal review, noted at that time by Geen, Brown and Pascoe (1991), was that the allocation formula should not allow operators who took large shares of the total harvest during the developmental phase of a fishery to gain permanent large shares through the subsequent allocation-process.
