Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This note extends the Kotlarski (1967) Lemma to show exactly what is identified when we allow for an unknown factor loading on the common unobserved factor. That is, this note completely characterizes identification of the model Y = cV + U and X = V + W, where the joint distribution of Y and X is known, while the constant c and the mutually independent random variables V, U, and W are unobserved. Potential applications include measurement error models and panel data factor models.