The threshold instrument is significant at the 1% level and the first stage F statistic is 10.5, suggesting that a weak instrument bias is not a substantial concern in this context.
Notice the stronger underestimation and change in the overall shape for all latitudes clearly visible in September 2009 when the state of the GOME-2 instrument was significant altered after a throughput test.
The marginal effects for the Probit model and the IV Probit are also reported in Table 8.c In the two-stage least squares estimation and the IV Probit, the first-stage estimation shows that our instrument is significant (refer to Table 7 for test statistics).
However, in the IV-FE models, although the instruments are strongly significant, the coefficients of both measures are not statistically significant at the 5%% level.
If the instruments are measuring significant changes in life due to major events such as diagnosis of serious disease, surgery, chemotherapy, and remission, then the location and method of administration of the instrument should have minimal effect on responses.
Ensuring the sensitivity of the instrument and detecting changes that are significant for the patient requires instruments specific to the study objective as well as the population of interest to be developed.
Whilst there were minimal within-tester differences in time taken to score with iCAHE, or AGREE II instruments, there were significant between-tester differences (p < 0.05) when using either instrument.
For nearly all reference instruments there were significant differences in mean scores between respondents with and without problems in the various EQ-5D items and strong correlations with the EQ Visual Analogue Scale and the EQ-5D index scores.
