The phrase "evidence is difficult to" is correct and usable in written English.
It can be used when discussing a topic where obtaining or presenting evidence is challenging or problematic. Example: When investigating complex fraud cases, gathering conclusive evidence is often difficult to achieve, making it challenging for prosecutors to secure convictions.
But that kind of evidence is difficult to obtain because baseball investigators lack the authority of law enforcement.
Vegliot evidence is difficult to interpret, as ē does not seem to have provoked palatalization, whereas ĕ, ĭ, and u did so.
The strength of the evidence is difficult to assess, because the government has kept much of it secret and because of questions about whether some was gathered through torture.
There's been scant evidence of abuse so far in Oregon, Washington and Montana, the three states where physician-assisted death is already legal, but abuse — whether spousal, child or elder — is notoriously underreported, and evidence is difficult to come by.
If we take the example of rape, the evidence is difficult to decipher.
This long list, mainly based on pathophysiologic considerations and supported by only weak evidence, is difficult to apply at bedside.
Forensic evidence was difficult to gather because bodies had been buried and bullet-scarred walls had been repaired.
However, observers inside the court said the prosecution evidence was difficult to follow or to understand.
However, the constraining pull factors like local government's involvement and their low demand for scientific evidence were difficult to overcome.
The use of non-citable research evidence was difficult to define, as many guidelines, standards, and recommendations by international and national organisations are based on citable research but without explicitly showing the citations used.
Based on the available evidence it is difficult to determine the effectiveness of tags as a theft reduction measure, albeit there is suggestive evidence that more visible tags are associated with greater reductions in theft than less visible tags.
