In LCBC-UiO/Questionnaires: Package with functions to calculate components and sums for LCBC questionnaires

html <- knitr::is_html_output()
rd <- !html

The higher the absolute value of the final score, the more certain / clearer the classification. For answers that reveal greater uncertainty about the similarity (e.g. a greater proportion of "almost" and "don't know"), the value will be closer to zero.

Pair formula

For pairs where both have answered, the pair's average values for all score values are first calculated. That is Drop = (Drop1 + Drop2) / 2, etc., where Drop1 is the score value of the response from twin 1 and Drop2 is the score value of the response from twin 2 in the same pair.

equation <- "zygocity = (\\frac{drop{_1} + drop{_2}}{2} * 1.494) + (\\frac{stranger{_1} + stranger{_2}}{2} * 0.647 ) + (\\frac{dexter{_1} + dexter{_2}}{2} * 0.458) + (\\frac{belief{_1} + belief{_2}}{2} * 0.417) + (\\frac{voice{_1} + voice{_2}}{2} * 0.347) + 0.007"

katex::katex_html(equation)

katex::math_to_rd(equation)

The sign of this "pair score" is then used to determine zygocity in the same way as for "single": Negative value means double, positive value means single.

Single formula

If only one twin in the pair has responded, the following is calculated:

equation <- "zygocity = drop{_1} * 2.111 + stranger{_1} * 0.691 + dexter{_1} * 0.366 + belief{_1} * 0.481 + eye{_1} * 0.394 - 0.087"

katex::katex_html(equation)

katex::math_to_rd(equation)

The sign of this "single score" is then used to determine the zygocity: Negative value means double egg, positive value means single egg.

LCBC-UiO/Questionnaires documentation built on July 18, 2023, 6:45 p.m.