This constant is often applied by physics undergraduates and high school students. Although technically a variable as it invariably changes from experiment to experiment it has the honorific of 'constant'.
Riggs constant is whatever number can be inserted into your formulae to make it work so you can finish this effing prac and go home.
Those with a doctorate in physics or higher have no need of Riggs constant as they now have the clout to 'analyse the data'. Apparently this is a far more elegant method of 'getting the right answers'. Also known as applying appropriate scientific methodology by removing data that doesn't fit the equations.
Cynical undergraduates have often commented that there is very little difference between the two methods, faithfully standing by the idea that all data should be included in an experiment and removing data that doesn't fit is a 'cop out'.
Even more cynicial lectures point out that there is a high correlation between those who don't receive their diplomas and those who state this particular belief.