To avoid interobserver error
in methodology, it was measured and recorded only by one person.
The average differences in degrees between the benchmark and the measurements made by the observers were defined as interobserver error, and this in turn was used as the variable that determines reproducibility for each angle measure.
In the measures taken in both the manual digital radiograph tracing and the digital radiograph image imported to Cephapoint, the interobserver error and standard deviation displayed in table 1 show levels above 7.
The FH/N/Pg angle had the smallest interobserver error difference (0.
The G'/Sn-Pg' angle presented greater interobserver error difference in the manual tracing, since the Subnasale point has a higher average error on the X axis; also, it is hard to locate the Pogonion on a curve, as reported by Chen.
We then removed all traits expressing no variation (either 100% or 0% in the combined sample), showed high initial interobserver error, or for which tetrachoric correlations could not be computed due to zero denominators.
Edgar and Aubry collected data and performed an interobserver error test using 11 of the above 12 traits on 30 dental models that were not part of this study.
To determine whether interobserver error would have skewed the distance matrix results, we performed a Pearson correlation between the calculated Cohen's kappa values and the trait frequency weights for PC1 (57.
They found out that all points show similar reproducibility in both types of radiographs, except for these points: infraorbital, posterior nasal spine, joint, porion, and basion, with direct digital image presenting the lowest interobserver error.
The average distance in millimeters between the reference parameter and the localizations identified by the observers was defined as interobserver error, and this in turn was used as a variable to determine each point's reproducibility.
In conventional images, the points with the highest interobserver error average in the X axis were menton (0.
The accuracy of estimating size by standard otoscopy is limited not only by interobserver errors
but by the fact that most perforations are not uniformly round.