However, some factors have been shown to decrease their effectiveness such as shortage in faculty, small faculty to students' ratio, difficulty in visualisation of the demonstration by students, and time constraints.
This raises its own difficulty, namely that ratios are not defined for infinite collections.
However, even for projects with a very high cost benefit ratio, difficulties in the planning process as well as legal controversies might significantly delay or even prevent the investment.
These papers highlight the difficulty of defining ratios without contextual role descriptions, for example, the roles of physiotherapists in the emergency department may vary from triage, undertaking first contact responsibilities or more conventional practice of referral from medical practitioners.
The differences are due to the difficulty in determining the ratio of surface to upper-level wind speeds in typhoons, particularly for regions of complex topography.
The property of the invariance of the ratio of difficulty across items (that is this ratio between any two items is constant, irrespective of the ability of the students) is again an essential requirement for measurement.
This method is an adaptation from the nearest neighbour technique (described by Silverman [ 13] and Altman [ 14] among others, and tested by Bithell [ 7]) to the difficulty of computing the ratio of two intensity surfaces.
Economies with big public spending to GDP ratios have difficulty growing.
The ICER figure is not presented with a CI due to difficulties in interpreting a ratio of two random variables.
Regarding the instrument groups the odds ratios for difficulty in playing (impaired or changed way of playing), in daily activities at home, and in doing leisure activities were all statistically significantly lower for the woodwind players compared to the high string players, see Table 6.
