The Ledermann bound is given by the solution \(k\) for \((M - k)^2 \geq M + k\), where \(M\) is the number of indicator variables. The maximum possible number of factors is the largest integer smaller than or equal \(k\).
LedermannBound(M)an integer indicating the number of indicator variables or a matrix of data, in which case ncol(M) is used as the number of indicator variables.
The Ledermann bound, a positive real number.
Tom Wansbeek and Erik Meijer (2000) Measurement Error and Latent Variables in Econometrics, Amsterdam: North-Holland. (note p169.)