On one hand, it is due to the unperturbed part and solving the linearized equations being more complicated in a KAM iteration; on the other hand, it makes the measure estimation very difficult since there are so many non-resonance conditions to be satisfied.
"The measures are very difficult to enforce and the public reaction is very, very dynamic and whoever is in the next government or if this government continues will have a much, much harder time".
When listed buildings are used as museum, achieving the same effectiveness level of typical energy efficiency measures is very difficult and, if possible, very expensive.
After a multimillion-dollar lobbying effort by the credit industry, this measure made it very difficult for middle-class people to file for bankruptcy using Chapter 7, which liquidates debt.
I think the proof that we've been successful with Guinea Worm will be not only an inspiration to others, but a confidence building measure that something very difficult can be done".
Even with a more error-proofed measure it is very difficult to rank providers (physicians or hospitals) accurately due to problems of collecting accurate data across multiple sites, challenges of attribution, and difficulties in forming comparable risk cohorts.
Both previous strategies have been abandoned before their success was measured, making it very difficult to find evidence of consistent improvement.
In this context, further improving the aggregated level of these measures might be very difficult and questionable in terms of economic benefits.
Complex pathogen dynamics, small patient populations and rapid patient turnover make the observation of the efficacy of different infection control measures in ICUs very difficult.
Educational measures are generally very difficult to obtain since most are compiled only on an annual basis (standardized test scores, graduation rates, college enrollment, etc).
