For those who know them, I think measurements like CXA, Grabb-Oakes should be recorded the same way. Whenever you dichotimize variables, you are actually erasing information that could be useful.
I was originally thinking about recording in the survey the exact numerical values of parameters like CXA, Grabb-Oakes, BAI, etc. But in the end I decided against it, because:
(a) People may not enter this measurement data correctly (especially as Dr G uses the comma for the decimal separator, which confuses some people).
(b) Some neurosurgeons conceivably may not provide the actual measurement value, but may merely state that a certain parameter like the CXA is pathological. So I wanted to provide a simple response options, where you just need to select whether your CXA, Grabb etc is: normal, borderline and pathological.
(c) On his reports, Dr G provides the CXA, Grabb, BAI and BDI values in flexion, neutral and extension, so that's 12 values you would need to enter. Plus the values for translational BAI, translational BDI, dynamic BDI, dens over Chamberlain and cerebellar tonsil ectopia making a total of
17 values for respondents to type in. I thought that might be too tedious, and might put people off answering the survey.
(d) I am not sure that the precise values of these measurements really tells us much. What's more important is whether the values are pathological or not.
@JenB Iif you really think it is important, I can add 17 additional questions to the survey asking about these 17 brain measurements; but I think it may be a bit overkill, and might put people off answering the survey.
@valentinelynx,
@Mere72, what do you guys think of the idea of adding 17 additional questions to the survey, which ask respondents to enter the exact numerical values for their CXA, Grabb, BAI, etc measurements in flexion, neutral and extension?