HRQOL instruments with missing values
The reasons why the EQ-5D-5L indexes, subscales of the FACT-G and those of the EORTC QLQ-C30 tended to be missing when the EQ-5D-5L was placed last are not clear. However, the first possible reason is that answering the EQ-5D-5L’s general questions may be easier after responding to the disease-specific HRQOL instruments’ specific ones than before answering them. The second possible reason is that patients may tend to decide to respond to the questionnaire after looking over the questionnaire with the EQ-5D-5L placed last. This is because the last instrument may be the instrument recalled mainly in the decision-making process, since in psychology it is known that, in free recall-task, the last item in a word list is easier to be recalled than other items (called recency effect) [