Sentence examples for has been difficult to evaluate from inspiring English sources

Keith Owens, a spokesman for Zurich North America, said the claim has been difficult to evaluate.

Thus, it has been difficult to evaluate the state of the sea's marine environment.

Membership has been difficult to evaluate more recently; church officials give different estimates and often define membership differently, according to an individual's level of involvement.

In spite of its apparent simplicity, this idea has been difficult to evaluate empirically, and coadaptation of host and parasite traits is usually assumed rather than demonstrated.

The importance of the immune response against tumor antigens in virotherapy efficacy is now well recognized, however, its relative contribution versus the intrinsic oncolytic capacity of viruses has been difficult to evaluate.

The risk of transfer of an introduced transposon and/or associated transgene to unintended organisms has been difficult to evaluate.

The therapeutic effects of the Sonic hedgehog (Shh) have been difficult to evaluate because of its relatively short serum half‐life.

While fire shapes the structure of forests and acts as a keystone process, the details of how fire modifies forest structure have been difficult to evaluate because of the complexity of interactions between fires and forests.

Furthermore, studies on this disease have been difficult to evaluate and replicate due to low sample sizes non-reporting of risk effect estimates.

As staff in home care services work alone in the patients' homes, their professional competence in observing, assessing, and documenting health issues had been difficult to evaluate.

The use of participatory methodologies, with young people as the researchers, allowed certain questions to be investigated that otherwise would have been difficult to evaluate using professional researchers only.