We also measured the proportion of each "yes" response for each year of the search: 2008, 2009, and 2010-11 (12 reviews published in the first four months of 2011 were combined with the reviews published in 2010).
Willingness to contribute to this endeavor was indicated by providers' response to the first question of each survey which asked for a "yes" response if they agreed to participate.
For a "yes" response, the caregiver is asked to elaborate on how they deal with such situations.
The challenge related to this item is the establishment of a threshold for the minimum amount of information (i.e., number of characteristics) required for a YES response.
In order to quantify the entropy over trials, we first calculated the probability of a yes response for each run (over subjects and repeats).
For each of these questions, a "yes" response was assigned 2 points, an "in part" response was assigned 1 point, and a "no" response assigned 0 points.
Items 1, 2, 6, 7, 9, and 12 met the inclusion criteria for the logistic models (yes response rate ranges from 39%to78%8%, n = 23).
b n and % are given for the "yes" responses.
The marginal effect of each factor, that is, a change in the probability of a "yes" response (for an independent binary variable) or of a one-unit increase (for an independent ordinal variable), i.e. estimated percentage of incremental demands for ambulance use produced by socioeconomic factors, was also computed with the probit model.
Visual inspection suggested an increased negativity for yes responses compared to no responses in particular within the control group (see Figure 1 right panel, and Figure 3).
