How Do I Measure Ethics?
I used five quantitative measurements to assess the ethical results of decisions: Self-Gain, Other-Gain, Commonwealth, Equality, and Total Ethics.  These are appropriate for analyzing the decisions of individuals.
Self-Gain: To survive, Self-Gain, on the average, must be greater than zero.  This is a fundamental imperative - ethics is meaningless if one does not survive.  Within each encounter, the primary goal of Self-Agent is to maximize Self-Gain.  Self-Gain is a valid ethical goal, but not the only goal.
Other-Gain: The gain or loss Other-Agent sustains after an encounter.  If we seek cooperative, pro-social outcomes, then another ethical goal is to cause (or at least permit) Other-Gain to be greater than zero.  If we ignore Other-Gain, we do not have a system of ethics.
Commonwealth: This is a better measure of the ethical consequences of decisions.  As the sum of Self-Gain and Other-Gain, it quantifies how much both Agents gained or lost after the encounter.  Positive ethical decisions should produce positive Commonwealth after an encounter.  Ethically, we wish to maximize Commonwealth.  Though a good measure of ethics, Commonwealth is not perfect.  Even when it indicates great joint-gain, one Agent may have benefited from the encounter far more than the other.  The latter Agent might even have suffered a loss.
Equality: This is the absolute difference between Self-Gain and Other-Gain, rather than their sum.  This measurement complements Commonwealth.  Ignoring all other factors, it is better that an encounter produce equal gains for both Agents, rather than unequal gains.  Equal gains indicate that the encounter involved no exploitation or sacrifice.  Ethically, we wish to maximize Equality.  Mathematically, this means minimizing Inequality, which is the actual difference between Self-Gain and Other-Gain.  Like Commonwealth, this is not a perfect measure.  Both Agents may suffer equal losses after an encounter.  Inequality may be zero (perfect Equality), but with a negative Commonwealth.
Total Ethics: Our two complementary measures of ethics are Commonwealth and Equality.  I propose a best measurement of positive ethical results, Total Ethics, as the combination of Commonwealth and Equality.  Because Commonwealth and Equality have different metrics, we cannot directly add them.  Total Ethics is computed as the sum of the respective ranks of Commonwealth and Equality.  Moreover, as we shall see, Commonwealth and Equality will differ in their respective contributions as the encounter environment changes.  Commonwealth and Equality will correspondingly differ in their contributions to Total Ethics.
I also analyzed the ethical consequences of group membership.  Group dynamics require us to modify our definition of Total Ethics.  Where no groups are defined, one of our best measures of Total Ethics is Commonwealth, the sum of Self-Gain and Other-Gain.  A good ethical decision allowed both Self and Other to make gains.  But if we seek a single metric for the best Total Ethics of the group, our best measure would be:
Total Adjusted Self-Gain:  Adjusted Self-Gain is the sum of Individual Self-Gain (belongs only to the individual Agent) and a proportion of the Group Treasury (support or gain obtained from group membership).  Total Adjusted Self-Gain is the sum of Adjusted Self-Gain for all group members.  Because the Other-Agent is a member of the same group, the Other-Gain of an individual encounter contributes to the group’s Total Adjusted Self-Gain.  The summing of Commonwealth is redundant, because Other-Gain is a component of Total Adjusted Self-Gain.
Note the levels at which these metrics are applied.  For an individual Agent, Adjusted Self-Gain is the best measurement of gain or loss.  However, an individual’s Adjusted Self-Gain could be achieved at the expense of the Group Treasury, or by forcing even greater losses upon other group members.  At the group level, Total Adjusted Self-Gain is the best (though not only) measure of Total Ethics.  If an individual achieved a high Adjusted Self-Gain at the expense of other group members, this ethical deficit would be reflected in the group’s total.  Maximizing Total Adjusted Self-Gain is a valid ethical goal (perhaps the best goal).
We have two complementary measures of Total Ethics, the group analogs to Equality as described above:
Total Equality:  This is the sum of the Inequalities for all within-group encounters.  The lower this sum, the better.  The lower this total, the more equal the average outcome between two group members after an encounter.
Spread of Adjusted Self-Gain:  Each individual within the group has a final Adjusted Self-Gain.  But some may have far greater (or lesser) Adjusted Self-Gains than others within the group.  All other factors being equal, we would prefer an outcome where there is less spread among the Adjusted Self-Gains of the group