Can grading love and care (and other goods) be an injustice?
It is a widespread intuition that some things in life cannot and should not be measured. For example, quantifying our love for a partner seems problematic. We do not want to rate our affection on a scale of 0-100.*  It is an important question, though, whether we can have a complaint of justice about measuring certain goods.  Here I consider two lines of argument for thinking that measuring certain things in quantifiable terms can be objectionable.
The first is indirect. It concerns unjust effects of things being measured that were not measured previously. An example is the measurement of the willingness to pay for parking spaces, which Joshua Kopstein recently discussed. Some start-up companies have developed apps through which people bid for spare parking spaces. Kopstein suggests that this system turns a public good into a private good that is allocated according to willingness and ability to pay, thus privileging the rich. This example does suggest that certain kinds of measurement can lead to complaints of justice, if they introduce an allocation mechanism that is not appropriate for the good. But in such cases it is the possibility of wrongful use, not the measuring itself, that can be criticized.
The second way in which measuring could raise complaints of injustice is more direct. Consider a stylized example. Assume that elderly relatives have a legitimate claim to receive some acts of love and care from younger family members. Assume that a start-up company develops an app that evaluates family members, on a score from 0 to 100, on how well their acts deliver care to elderly relatives. And assume that using the app becomes a social trend, such that most people start using it. This might have some beneficial effects. For example, it might become easier to share knowledge about how to cheer up grandma “efficiently” when she is gloomy. But could it also mean that what the elderly relatives receive are not, any longer, acts of love and care, but something else: acts calculated to enhance the wellbeing of elderly relatives? If this is the case, it seems that they could raise a claim of justice. They are denied what they have a legitimate claim to receive. Schematically put, they have a legitimate claim to good X (love and care), but what they receive is good Y (acts that will efficiently enhance wellbeing), because by measuring and quantifying X, it is transformed into Y.
One problem here is whether we can specify a sufficiently clear and plausible account of what good X is and why good Y is different from it.** One possible issue might be that good X is a complex and multi-dimensional good, but by measuring it, we necessarily reduce it to fewer dimensions. Although modern technologies offer increasingly sophisticated ways of measuring things, they still cannot capture all the dimensions of what it means, for example, to have a trusting and loving relationship with someone. Another issue could be that offering good X requires openness to new challenges or a certain degree of spontaneity. Again, these cannot be easily captured in quantitative terms and are, thus, likely to be excluded if one tried to measure X. For example, an important aspect of a loving relationship is that one is sensitive to subtle changes in the other person’s situation, and maybe even that one understands such changes before the person herself fully understands them. It is therefore unclear how they could be included in quantitative measures.
Certain forms of measurement may be simply dysfunctional. In finance, there is Goodhart’s law: “When a measure becomes a target, it ceases to be a good measure.” This might also hold for other areas and make it simply unwise to try to utilise measurements there. But in additional to dysfunctionality, we should not exclude the possibility that measuring certain things may be an injustice.  At least in the case of care and love, it seems there is reason to believe that that is the case.
*In Dave Egger’s The Circle there is an episode in which one of the protagonist’s lovers asks for an evaluation of his qualities, on a scale from 0 to 100, directly after the sexual act. The protagonist is somewhat startled, and then resorts to a white lie.
**Aspects of this question have been explored in the debate about limits of the market, where one concern is whether the socially defined “meaning” of goods can be a basis for not measuring goods in market terms. See for example Debra Satz’s discussion of Elizabeth Anderson’s approach in her Why Some Things Should Not Be For Sale.