After opening the first package, patients completed a questionnaire.
They filled out a similar questionnaire after opening the
second package. The questionnaire included a consumer satisfaction
index to measure satisfaction with the food containers. This
index was adapted from a method applied in finance (Suchanek
et al., 2010). It consists of two parts, including eleven questions
answered on a six-point Likert scale. Part one determines patients'
general expectations of a food container; in part two, patients rate
their general satisfaction with the test product and satisfaction with
individual product characteristics. The results give a satisfaction
index between 0% and 100%. Higher values represent greater
satisfaction. Subjective difficulties perceived during the opening
process, such as the force required, tear tab size and palpability, were also recorded and graded on a scale of one (worst) to six (best
value).