This paper tests four models of the effect of the size of a subgroup of an organization on the proportion of attraction choices made by members of the subgroup that are given to other members of the subgroup. The data base consists of friendship and respect choices made by members of the Maryland State Police force. The four models are: simple linear, linear logarithmic, threshold, and logarithmic threshold. In addition, the effects of the bureaucratic functions of the subgroup on in-group choosing are tested. Though all of these models yield significantly good fits to the data used, the logarithmic threshold model provides the best fit. This model describes the process of in-group choosing (friendship and respect) as a positive linear function of the logarithm of the size of the group, provided the group is below a critical size, somewhere around 50 to 70 members. Above the critical size, there are no consistent changes in in-group choosing with increasing size. (Author)