Thus, we considered our sample size (N = 302) adequate for the estimation of difficulty and discrimination of TDE-II items.
The finding that perceived difficulties in almost all gait-related physical activities, such as walking, running, hopping, and climbing stairs negatively predicted the performance in the 6MWT may indicate that the estimation of difficulty level is likely to be accurate and may be used to assess the task's real difficulty.
A simple Rasch model, with relatively few parameters and a straightforward estimation of the difficulty parameter, was chosen.
Firstly, the preoperative estimation of level of difficulty was performed with the patient under anaesthesia.
The ordering based on the item difficulty parameters was in line with the ordering based on the estimation of the items' difficulties by our expert group, and the easy, moderate, and difficult items were included in the final version.
The ordering of the items based on their locations on the latent dimension (i.e., their difficulty; see also Table 2) is in line with the ordering based on the estimation of the items' difficulties by our expert group in the test development process.
The quality of the aggregation can also be improved by using estimations of the difficulty level of tasks and skills of workers [103].
In order to optimize the logistic patterns of operating theatre, next to accurate day case management, it is mandatory that surgeons planning hysterectomy make adequate estimations of the difficulty of surgery [6, 7, 8].
The big error range using a FNM tool is a potential risk because of difficulties on estimation of system resistances and airflow distribution.
Difficulties of single or multiple dipole approaches emerge from the distributed character of most cortical activations, which is misrepresented by dipoles, inaccuracies in the estimation of source depth, and difficulties in a priori determining the number of sources (see, e.g., Hauk 2004; Huang et al. 2006).
There have been discussions that the PCA method is less suitable for risk estimations of dietary patterns, because of difficulties to find plausible linkages between dietary patterns and the observed disease [ 30].
