By creating at least two related raw counts n and n.sub.i, of particles in a fluid suspension as at least two physically derived particle counts, there can be developed a mathematic function relationship by which the "scanning constant" k of a particle analyzer, for example of a Coulter type, can be factored out and a resultant equation obtained. The resultant equation is employable, for instance, in operating upon the input n and n.sub.i raw counts for generating the ultimately desired corrected particle count N.sub.i which largely eliminates particle coincidence errors. The disclosure encompasses several methods and apparatuses by which the raw counts are developed and by which the related mathematic functions are defined and then employed to obtain corrected counts. Specially considered are multichannel analysis and optical apparatus for facilitating the count correction.