Qualitative and quantitative interpretations of the least restrictive means

Abstract Within healthcare ethics and public health ethics, it has been the custom that medical and public health interventions should adhere to the principle of the least restrictive means. This principle holds that public health measures should interfere with the autonomous freedom of individuals to the least possible or necessary extent. This paper contributes to the discussion on how best to conceptualize what counts as the least restrictive means. I argue that we should adopt a novel, qualitative interpretation of what counts as the least restrictive means. Based on the multidimensional framework of the capability approach, the qualitative interpretation holds that the least restrictive means should be measured in terms of whether it restricts certain normatively valuable freedoms. I contrast this interpretation with quantitative interpretations that measure how much, or the extent to which, a public health measure interferes with the freedom of individuals.


| INTRODUC TI ON
Within healthcare ethics and public health ethics, it has been the custom that medical and public health interventions should adhere to the principle of the least restrictive means. 1 In general, the principle of the least restrictive means holds that public health measures should interfere with the autonomous freedom of individuals to the least possible or necessary extent. As a tool for applying the principle of the least restrictive means in practice, the Nuffield Council of Bioethics has developed the influential 'intervention ladder', which visualizes increasingly restrictive public health control measures as rungs on a ladder. 2 However, it is not always clear what is meant by this principle. This paper contributes to the ongoing discussion on how best to conceptualize what counts as the least restrictive means. I argue that we should adopt a novel, qualitative interpretation of what counts as the least restrictive means. Based on the multidimensional framework of the capability approach, the qualitative interpretation holds that the least restrictive means should be measured in terms of whether it restricts certain normatively valuable freedoms. I contrast this interpretation with more common, quantitative interpretations that measure how much, or the extent to which, a public health measure interferes with the freedom of individuals.
The paper is structured as follows. In Section 2, I provide a short introduction to the concept of the least intrusive means within healthcare ethics ad public health ethics and present the intervention ladder proposed by the Nuffield Council of Bioethics. In Section 3, I argue that the intervention ladder exemplifies a quantitative interpretation of the least restrictive means. In Section 4, I introduce and develop a qualitative interpretation of the principle of the least restrictive means 1 based on the capability approach. In Section 5, I present and discuss three objections to the intervention ladder and the quantitative interpretation that it exemplifies. Finally, in Section 6, I argue that unlike either of the quantitative interpretations, the qualitative, capabilitybased interpretation of the least restrictive means can address all of the three objections raised against the intervention ladder.

| THE LE A S T RE S TRI C TIVE ME AN S AND THE INTERVENTI ON L ADDER
In order to curb the spread of infectious diseases, public health professionals often implement measures, such as mandatory vaccination, namely proportionality and least infringement. 5 The condition of proportionality holds that in the context of a measure that promotes public health yet infringes on some more general moral consideration -such as individual autonomy, privacy, confidentiality or prior government promises -it must be shown that 'the probable public health benefits outweigh the infringed general moral considerations'. 6 In other words, it must be shown that the infringement is proportional to the benefit to public health: isolating someone with a common cold for days would not usually be considered a proportionate response because of the low cost of treating the common cold and the low risk it poses to public health. If a public health measure meets the condition of proportionality, and can be shown to be the kind of measure that is both effective and necessary to address the particular public health concern, the least infringement condition then holds that the degree to which a general moral consideration is infringed should be to the lowest degree consistent with achieving the public health goal.
The principle is also sometimes referred to as the principle of the least intrusive means or the least restrictive alternative. In other words, because, or insofar as, we regard individuals to have the capacity for self-determination, we ought to protect their freedom to make autonomous choices. Thus, at the core of the principle of the least restrictive means is a commitment to reduce the impact of public health measures on individual freedom to the least extent necessary or possible.
How can the principle of the least restrictive means be put into practice? How can it help us to evaluate actual public health measures? One influential instantiation of the principle of the least restrictive means, and the normative value of autonomy, is the 'intervention ladder', proposed by the Nuffield Council of Bioethics. 12 Table 1 presents an adapted version of the intervention ladder that applies it to the context of infectious disease control.
The ladder should be read in the following way, according to the authors. At the bottom of the ladder, we find the least restrictive alternative, namely to do nothing or simply monitor the situation. This is the least restrictive means because it does not involve any restrictions on the autonomous choice of the individual. Moving up the ladder, the higher rungs aim to increasingly influence the choice of the individual by providing additional information, guidance, incentives and disincentives. At the top of the ladder, we find the most restrictive means, which involve, first, a decrease in alternative options and, finally, the complete elimination of choice.
The higher up the ladder one goes, it is argued, the stronger the justification of the implemented means needs to be. The authors clearly hold that a stronger justification is necessary because of the increased infringement on individual freedom and autonomy, the higher up the ladder one goes. Consider, for example the following statements: 'The most intrusive is to legislate in such a way as to restrict the freedom significantly'; 'A more intrusive policy initiative is likely to be publicly acceptable only if it is clear that it will produce the desired effect and this can be weighed against the loss of liberty that will result'; and, 'the benefits to individuals and society should be weighed against the erosion of individual freedom '. 13 It is possible, however, to restrict the freedom of individuals in different ways and it is not exactly clear in what way the authors intend the intervention ladder to be interpreted. In particular, it is possible to advance both quantitative and qualitative interpretations of what it means to restrict freedom to the least extent possible.
On the quantitative interpretation, the least restrictive means is the measure that restricts the range or amount of freedoms that an  The difference between these two interpretations is evident in how they can be applied in practice to evaluate and trade-off competing public health measures. As argued at the top of the section, within public health it is often necessary to make difficult decisions that balance effective intervention with a concern for protecting individual autonomous freedom, and that interventions should adhere to the least restrictive means in this regard. Yet, how we conceptualize individual freedom -that is, in terms of quantity or quality -determines how we balance or trade-off these concerns. or valuable might be highly context-specific, but in the case of the alternative measures proposed above, proponents of the qualitative interpretation are likely to arrive at different conclusions than proponents of the quantitative interpretation. For example, while they might agree that a tax on junk food is too restrictive out of a normative concern for equality, they might be less inclined to object to the ban on sugary drinks in public institutions because, ex hypothesi, buying sugary drinks does not constitute a valuable choice in and of itself. Moreover, and contrary to the preferred option on the quantitative interpretation, insofar as a healthy lifestyle is arguably a valuable choice and insofar as public-awareness campaigns are less effective at promoting healthy lifestyles, proponents of the qualitative interpretation might object to such interventions because they risk interfering with individuals' actual freedom to achieve a healthy lifestyle, for example by not addressing personal obstacles, such as akrasia, or structural issues, such as socioeconomic inequalities, which are important drivers of obesity.
This raises the question that I will address in the remainder of this paper: when push comes to shove, should public health professionals prioritize the concern for the amount of alternative choices that people have (i.e., the quantitative interpretation) or the concern for whether the choices that people have represent valuable options (i.e., the qualitative interpretation) when choosing between alternative public health measures?
In the following two sections I introduce and discuss these two interpretations in greater detail and show how the intervention ladder exemplifies the quantitative interpretation. In Section 5, I argue that the overlap with the quantitative interpretation makes the intervention ladder vulnerable to three objections that, as I argue in Section 6, only can be addressed by adopting the qualitative interpretation of the least restrictive means.

| THE QUANTITATIVE INTERPRE TATI ON OF THE LE A S T RE S TRIC TIVE ME AN S
The first interpretation of the principle of the least restrictive means focuses on how much, or the extent to which, a public health measure interferes with the range of freedoms and choices that individuals have. I call this the quantitative interpretation of the least restrictive means because it is primarily concerned with the quantity of alternative options that people have and the extent to which public health measures interfere with and restrict this range of options.
The quantitative interpretation of the least restrictive means builds on the (libertarian) claim that more freedom is better than less freedom. According to this view, freedom is something that be mea- | 515

BYSKOV
If we take autonomy to be the primary moral concern, in this way, the quantitative interpretation is intuitively attractive because it aims to leave as much opportunity for autonomous choice as pos- qualitative interpretation of the least restrictive means. In the next section, I proceed to introduce this qualitative interpretation.

| A QUALITATIVE , C APAB ILIT Y-BA S ED INTERPRE TATI ON OF THE LE A S T RE S TRIC TIVE ME ANS
The least restrictive means in quantitative terms is not always the measure that is the most desirable, neither from a public health perspective nor from the point of view of individual agents. In the first case, as argued, less restrictive means might be less effective to achieve public health aims than interventions that interfere more with the choices of individual agents. In the second case, the least restrictive means in quantitative terms might fail to protect certain qualitative concerns, such as socioeconomic equality.
Contrary to the quantitative interpretation, the second way in which the principle of the least restrictive means can be interpreted aims to take these qualitative considerations of freedom into ac- For example, the isolation of infected patients may not only affect their freedom to move around, but also their ability to engage in social relations and participate in recreational activities. Likewise, two different individuals may experience different impacts from the same public health measure. Someone who is less socially active would be less affected by being isolated from friends and family than someone who values social relations higher.
By focusing on what people are able to do or be (i.e., their capabilities), the capability approach aims to broaden the informational basis of traditional behavioural models and evaluative accounts. 21 What is missing from these models, according to Sen, is an account of how people value the different choices that they have and what makes certain freedoms more valuable or normatively important than others. As Sen argues, a singular concern with the quantity of freedoms that individuals have would be unsustainable because it would: … be then possible to assess the freedom of a person independently of -or prior to -the assessment of alternatives between which the person can choose … It is odd to conclude that the freedom of a person is no less when she has to choose between three alternatives which she sees respectively as 'bad', 'awful', and 'gruesome' than when she has the choice between three alternatives which she assesses as 'good', 'excellent', and  In the following I argue that the quantitative interpretation (and, hence, the intervention ladder) is subject to these three objections and show how they can be addressed by adopting the qualitative interpretation of the least restrictive means. framework that can be further specified into more particular capability theories. 30 While the capability approach at its core is normatively committed to conceptualize people's well-being in terms of their real freedom to do or be certain things, when developing a particular capability theory -such as a capabilitarian interpretation of the least restrictive means -it is necessary to take other normative concerns into consideration, such as equality, equity and efficiency. In other words, neither the capability approach in general nor its more specific capability theories are exclusively concerned with individual freedom.

| Concern for other values than freedom
Secondly, the capability approach acknowledges that people are not only concerned with their individual freedom, but also other values, such as fairness, equality, equity and efficiency. What this means for the interpretation of the least restrictive means is that it cannot simply be reduced to the measure that restricts individual freedom to the least extent, measured in quantitative terms as a range of options or choices. Rather, if we care about these additional values, the least restrictive means would be the one that is most cost efficient in terms of balancing individual freedom and effectiveness or the one that preserves the most equal amount of freedom among affected individuals.

| Some freedom-restricting interventions are necessary to protect valuable freedoms
The second objection points out that not all interventions restrict the range of options that individuals are free to choose from. 31 For example, as on rungs 6 and 7, the enabling of choice, by providing additional options, and the provision of information seem actually to enhance the freedom of the individuals. Offering access to eradication treatment is not antithetical to individual freedom of choice. 32 In fact, it provides infected individuals with a greater freedom to combat their disease -an opportunity that they might not have, or only would have had to a lesser extent, had this access not been provided.
It might be argued that the above example only shows that the relevant kind of intervention is one that also entails some interfer- We can likewise respond to these amendments in two ways.
First of all, it is wholly implausible to reduce individual freedom to only concern the negative aspects freedom, ignoring the gain in positive freedom. For example, for someone to have the negative freedom to choose between vaccinating or not (i.e., no one will interfere with this choice), they would also need to have the positive freedom to vaccinate. Since, in the above example, the positive

| Some freedoms are normatively more relevant, important or valuable than others
The third objection holds that a quantitative interpretation of the intervention ladder fails to accommodate the idea that some free- Recall, for example, the case of obesity in Section 2 and how proponents of the quantitative interpretation might take concerns for equality (i.e., taxes on junk food unequally affect the choices of less affluent individuals) into consideration when deciding on appropriate measures to address obesity.
Although this example indeed shows how the quantitative interpretation of the least restrictive means can take qualitative concerns into account, this concern can still be reduced to a quantitative concern, namely a concern that the amount of freedom of some individuals is reduced, rather than a concern with the actual qualitative notion of social and economic equality. An actual concern for socioeconomic equality might lead public health professionals to accept a loss in individual freedom of choice, but proponents of the qualitative interpretation are not ready to make this sacrifice. Thus, they face a dilemma. On the one hand, they can insist, as I argued in Section 5, that the quantitative interpretation includes a ceteris paribus-clause, holding that only after taking all things into consideration should we choose the measure that is quantitatively superior, in which case the quantitative interpretation is actually not a quantitative position because it gives priority and precedence to qualitative concerns. On the other hand, avoiding this reduction into a qualitative interpretation, the proponents of the quantitative interpretation could reaffirm the commitment to prioritize the concern for individual freedom of choice by insisting that the least restrictive means is the one that protects the largest amount of individual options or, conversely, restricts the least amount of alternative choices.
Accordingly, I contend that we should adopt a qualitative interpretation of the least restrictive means. While both interpretations are concerned with the value of freedom, the qualitative interpretation holds that the infringement of public health measures on individual autonomy should first and foremost be measured, not in terms of the amount of overall freedom that they restrict, but rather in terms of whether certain valuable freedoms are infringed upon.
Taking into account the quality of the freedoms that individuals have to choose from better reflects the values that are at stake when implementing public health measures, including the general moral considerations that Childress et al. highlight, and might even be more reflective of actual public health practice in which public health professionals and decision makers do put such non-quantitative concerns front and centre. 37 Moreover, it provides a rebuke to the libertarian strand of public health ethics and policy.
Lastly, it should be noted that I have not here investigated whether this qualitative, capability-based interpretation is compatible with the intervention ladder or whether it entails that we should abandon the ladder as an illustration of the least restrictive means.
However, as Dawson concludes, 'if we count more than liberty as relevant, we cannot use the intervention ladder'. 38 I will let it be subject to further research whether this holds true and, if so, how to best represent a qualitative, capability-based interpretation of the least restrictive means.