In an article by Santacreu et al. (2006) there is a mention of altruism assessment within the framework of the Character Education Inquiry (CEI):
If we return to the first half of the last century, we can find important precedents of objective assessment of Personality that were embodied in solid and coherent research programs carried out by important authors in this field. Amongst these, works by Hartshorne and May (1928, Hartshorne, May & Maller, 1929, Hartshorne, May & Shuttleworth 1930) must be mentioned. These authors developed a set of tests included in their Character Education Inquiry (CEI) oriented, amongst other things, to measure honesty or altruism.
At the present moment I do not have access to the report of the CEI to verify how Hugh Hartshorne and his colleagues were assessing "honesty or altruism". However, Robert W. Friedrichs (1960) cites the report of the CEI (along with a couple of other investigations) and claims that these studies did not have as their objective the assessment of altruism. These, so he implies, are the only studies undertaken in the field of psychology which may attract attention of those interested in the study of altruism. I tried to find attempts at objective assessment of altruism in the work published since 1960, but without success. So I'm here looking for assistance.
I admit that I may use the term 'objective test' incorrectly. In order to exclude any misunderstanding I would like to add that I conceive of objective test designed to assess altruism as simulated conditions in which an individual (or a group of them) is put at a moral choice being unable to uncover the simulated nature of the proceedings or to identify the qualities under scrutiny. I will be very grateful to all who help me to find reports of applications of such methods to the assessment of altruism.
Santacreu, J., Rubio, V. J., & Hernández, J. M. (2006). The objective assessment of personality: Cattells's T-data revisited and more. Psychology Science, 48(1), 53.
Friedrichs, R. W. (1960). Alter versus ego: An exploratory assessment of altruism. American Sociological Review, 496-508.