The selection of a measurement method is a very important step in the creation of any measurement procedure; unfortunately, its importance is not always fully appreciated. However, it is the method that is the kernel for further generation of the methodology and thus primarily determines the performance of the whole measurement procedure. We carried out a purposeful detailed investigation of the cohesion of the Agenda 2030 vision and past experience in measuring human development to make an informed choice.
3.1. Direct Measurement Method
“In direct methods of measurement, the unknown quantity is directly compared against a standard and the result is expressed as a numerical number and a unit” (see, e.g., [
26]. Direct (absolute) measurement of the achieved progress in sustainable human development and obtaining the measurement result as one quantity value is impossible due to lack of a standard (etalon).
That is why the SDG indicators’ set, which was adopted by the UN General Assembly, consists of 232 narrow profile indicators only [
27]. A huge advantage of the set is its relatively widespread use of hard statistical indicators; they provide a representative view of the relevant part of aspects of sustainable development. Nevertheless, not all SDG indicators can be quantified; the global data availability is low (about 50%, according to [
28]), especially for reliable data. The similarly purposed Eurostat database provides the data on 100 indicators for EU countries only [
29].
With such a huge number of indicators, uneven execution occurs in various aspects (targets); similar progress for all aspects is unthinkable. An analysis of the Agenda 2030 implementation trend reflects that part of the individual indicators show progress, others show mining at the current level with some fluctuations while still others show regression in the relevant aspects.
The UN High-level Political Forum on Sustainable Development [
30] was held to comprehensively review the achieved progress. In assessing progress, successes as well problems were mentioned only on individual aspects, e.g., access to safe drinking water and electricity, child and neonatal mortality, economic growth, quality education, poverty, hunger, gender equality and environment. Progress as a whole and the general dynamics had not been assessed; leaders and those falling behind were not identified. Due to the
Agenda 2030 key thesis on integrity of the sustainable human development process, the forum had to give a political conclusion on the overall progress, and it did: “… yet it is clear that the world is not on track to meet the SDGs by 2030”. However, it is difficult to consider it as a data-based conclusion.
Assessments at EU [
28] and OECD [
31] levels had an analogous fragmented structure. Analysts were also forced to draw conclusions about the overall trend based on individual indicators only and using an indefinite conclusion on “… only limited progress” [
32].
There are several additional reasons as to why obtaining a positive result by creation of a composite index aggregating many specific target-related indicators (the so-called bottom-up approach) in this case is questionable.
As the integrated essence of multidimensional sustainable human development, the overall progress of
Agenda 2030’s implementation cannot be adequately characterized, even by a combination of many sectoral numerical indicators “because these [social, economic, and environmental] resources are interconnected, there are no simple solutions to the problems society causes” [
33]; e.g., the economic growth affects investments in social and environment dimensions, knowledge drives the economy and creates awareness of the environmental issues and the polluted environment directly impacts health. Bennich, Weitz and Carlsen [
34] provide an extensive analytic overview of these interlinkages.
In turn, Barbier and Burgess [
35] show that many of the SDGs contribute to more than one dimension of sustainability; quantitative analysis of the interactions and complementarities convincingly confirms the existence of interconnections; 43% of the sustainable development indicators in the EU database are used to describe two or more SDGs. The actions taken and the relevant indicators do not always have a positive effect on all SDGs; a different and, in the medium term, even contradictory effect on overall progress is possible (e.g., the balance between economic and environmental activities is still being sought).
Nevertheless, there have been several attempts to create the index that directly integrates SDG-related indicators.
The Sustainable Development Goals Index (SDGI) methodology is directly based on the structure of 17 SDGs that is an advantage of the approach [
21]. The SDGI is created by summarizing part of the target indicators, which reflects the SDG settings; averaging the normalized indicators takes place first within the SDGs and then across SDGs.
Several weaknesses in the index methodology have been mentioned [
36,
37]. Only 60 (issue 2016) and 85 (issue 2020) of the accepted 232 SDG indicators are aggregated depending on the data availability to date. It is not known whether these are the determining indicators; this creates uncertainty in the calculated result. The methodology does not account for the interlinkages and the integrity of the SDGs.
The Systemic Indicator of Sustainable Development (SISD) is an academic attempt to remedy the last shortcoming of the SDGI and to measure the sustainable human development process in a more holistic manner [
38]. Applying the systems thinking theory and approach, the dataset of 47 indicators (the same data availability problem), which relate to 17 SDGs, is transformed into another set of 14 factors taking into account the complexity of sustainable development and interlinkages of the SDGs. These factors are aggregated as secondary indicators to create the SISD. At the current stage of elaboration of the index, the result has become difficult to interpret; the question of interlinkage at the factor level also remains.
There are also proposals for the creation of composite indexes at the level of individual SDGs [
39]. However, the bids are for some goals only and their aggregation to obtain a common index has not been elaborated.
3.2. Indirect Measurement Method
The essence of the indirect measurement method is synthesis of the unknown quantity from measurements made by direct methods of measurement of some other quantity linked to the unknown one by a defined relationship (see, e.g., [
26]). In the practice of measuring human development, several quantities (indicators), which are related to achievements of human development as a whole or its dimensions, are usually used. This (so-called top-down) approach makes the problems of the direct measurement method irrelevant: a lack of a part of individual indicators is insignificant, interdimensional links and impacts are observed and the impact of indicators on several targets and SDGs is considered.
Dimension indicators typically are aggregated as components in the composed index. Experts, politicians as well as the global community, already have long-term experience and habits for creating and using an exactly indirect measurement method of the achieved human development level.
“Gross domestic product is an aggregate measure of production” [
40], which is formed by the value added by all households, companies, public bodies and nonprofit institutions across the economy. It is a comprehensive indicator, which is constructed using datasets of the National Accounts and is based on the economic output, which is a principal advantage for data-driven high-level political decision-making. In fact, GDP not only summarizes the economy in one number, but “it drives government policy and sets priorities in a variety of vital social fields—from schooling to healthcare” [
41]. Therefore, “the success of GDP is based on the fact that, with them, politicians were from the outset able to pursue a whole array of goals beyond just documenting economic processes” [
42].
HDI is a politically accepted index, it has been used successfully for many years as “the best available alternative to GDP per capita” [
43], although problems have already been identified (see, e.g., [
44]). HDI is calculated as the geometric mean of three normalized dimension indexes (see
Figure 2), thus ensuring a balance between the dimensions [
45].
There are more suggestions for indirect measurement of sustainable human development compared with the direct one. Two of them propose the use of one or more narrow profile environmental indicators, others use integrated environmental indices. It should be noted that there are also offers that include other aspects such as peace, happiness and so on (see, e.g., [
46]).
The Human Sustainable Development Index (HSDI) [
47] was proposed by Togtokh and Gaffney “as a small step ahead to promote sustainable development” [
48]. It is created by the addition of an environmental dimension to the HDI. Although environmental health and the services, which ecosystems provide for humans, are mentioned as factors that increase quality of life, CO
2 emissions per capita is proposed as the only indicator representing the environmental dimension. HDI methodology is preserved; there is an equal weighting of all four dimensions (standard of living, longevity, knowledge and environment):
There are not many worldwide complex environmental indices that cover various environmental aspects as a whole.
The Ecological Footprint (EF) created by the World Wildlife Fund [
49] reflects use of the natural capital (soil, air, water, minerals and living creatures) as well as the amount of generated carbon emissions. This should be evaluated as an insufficient composition for its use as an environmental indicator. The authors of the report themselves acknowledge that “National Footprint Accounts are not capable to quantify human environmental damage or pollution”. Nevertheless, several authors have used EF to create sustainable human development indices.
The Ecological Well-being Performance indicator (EWP) [
50] is composed as the ratio of the HDI and the logarithmically normalized value (EFn) of the EF to measure the achieved level of sustainable human development in relation to ecological assets consumed:
Analysis shows that there is quite a strong positive correlation between the HDI and EF (see
Figure 3): a more developed economy and society is generally more resource intensive. The impact of the environmental dimension (EFn) on the calculated composite indicator is extremely strong, resulting in a moderate negative correlation between HDI and EWP. Such an introduction of the environmental factor crosses the economic, longevity and educational achievements of society.
The Sustainable Development Index (SDI) philosophy [
51], in general, is similar to that of EWP. HDI is slightly modified (HDIm), e.g., Gross National Income per capita (GNI pc) levels have been limited at
$20,000 PPS (Purchasing Parity Standard). Unlike EWP, the environmental dimension is formed by a complex function of material footprint (MF) and CO
2 emissions:
Correlations between the HDI and both MF and CO2 are strongly positive. The result in this offer is very similar to that of the EWP.
There is a clear need for a more integrated environmental indicator that covers as many aspects as possible and thus assesses the inevitable pressure of human development on the environment.
The Environmental Performance Index (EPI), which is compiled by experts from several prominent universities, has much wider coverage of environmental issues [
52]. It covers 11 high-priority environmental aspects (air and water quality and pollution, biodiversity degradation, climate change and emissions, waste management, etc.), for which 32 statistical indicators have been compiled for characterization. The index provides a balanced assessment of environmental health, evolving with increasing levels of knowledge and well-being, and the viability of ecosystems, which suffer from industrialization and urbanization.
Experts of the EC Joint Research Centre acknowledge the EPI “as a reliable composite indicator to measure environmental performance worldwide” [
53].
The Environmental Human Development Index (EHDI) takes a holistic approach [
54] to the synthesis of human development (which is characterized by the HDI) and environmental factor (EPI, as the most comprehensive environmental index is chosen). Based on the assumption of equal importance (resp. weights) of both mentioned components on sustainable human development, the index is calculated as the geometric mean of HDI and EPI:
Accounting for formula (1):
The environmental dimension has the same weight as the life, education and income dimensions in total. For example, a 5% growth in one of the HDI dimensions results in a 0.82% increase of the EHDI, while a 5% growth in the environment dimension provides a 2.47% increase of the EHDI. This is not as strong an impact of the environmental dimension as we have seen in the cases of EWP and SDI; nevertheless, it does not correspond to the Agenda 2030 setting on interdimensional balance. In fact, these examples reflect the regular efforts of radical environmental activists to limit the concept of sustainability to the natural environment only.
3.3. Selection of the Optimum Measurement Method
Several postulates arise from the investigation of the key principles of
Agenda 2030 and past experience in measuring human development (see [
55]). Currently, when experts and politicians are looking for a successor of the HDI to measure sustainable human development, it is important to take them into account to select the most appropriate measurement method:
The
Agenda 2030 general vision—“achieving sustainable development in its three dimensions—economic, social and environmental”—describes not only the development process but, firstly, the result achieved. Thus, respect is given to the principle already defined in the 1st Human Development Report [
13]: “Human development has two sides: the formation of human capabilities—such as improved health, knowledge and skills—and the use people make of their acquired capabilities”. The indirect measurement method makes it possible to create the AHDI by aggregating the indicators characterizing the results achieved in various dimensions of sustainable human development; this opportunity should be appreciated.
Assuming that any of the 17 SDGs, 169 targets and 232 indicators is, to some extent, the driving force of the Agenda 2030 vision, it is necessary to consider all indicators in the sustainable human development measurement process, if the bottom-up method is used. Many of these indicators could be insignificant and could be dropped, but which ones? It would be worthwhile to determine them using data mining methods, but before that, data on all indicators are necessary. While data for many indicators are not available, several indicators are not quantifiable at all, this is a fundamental obstacle to obtaining an adequate measurement. Applying the top-down method does not result in such a problem if appropriate result-oriented indices are used to describe dimensions of sustainable human development.
The interlinkages and integrated nature of the SDGs are of crucial importance when implementing the
Agenda 2030 vision; an indivisible, integrated approach is one of the basic principles of
Agenda 2030: “As already pointed out, many of the goals included in the SDGs are multidimensional, covering more than one dimension of sustainability. Many synergies and complementarities can exist among the different SDGs. But trade-offs are also possible where improvements in one dimension could trigger negative results in another” [
36]. When aggregating many individual indicators in a composite index, these features may be lost. When working with the resulting data, they will be considered.
The postulates show that the use of the direct measurement method is associated with great difficulties in creating the composite index for measuring sustainable human development, which will “be helpful in setting policy priorities and in benchmarking or monitoring performance” [
56], and will be understandable, transparent, acceptable and practicable for experts, politicians and the global community. The existing offers confirm that there is a long way to go in solving various problems, and there is no guarantee of a successful result.
Accounting for the SDGs’ and indicators’ crosslinks is of crucial importance. The final documents of the SDG Summit [
30] reiterate the necessity of a systemic and all-inclusive approach: “Focusing on one goal or target at a time and working in silos is therefore unlikely to result in overall success. Transforming to a socially, economically and ecologically sustainable society requires strengthening the focus toward all the SDGs and ensuring cooperation among the different measures or levers of action”. Furthermore: “The widely accepted
ceteris paribus condition, which analyses the behavior of each system independently, cannot be considered helpful in the
Agenda 2030 context. More holistic approaches are required as the contextual evaluation of several systems together is fundamental” [
36].
Experience shows that the indirect measurement method (used by both GDP and HDI) has been popular and practically applicable. “Top-down approach is less time and resource intensive and has been generally applied at larger geographical scale; …it is driven by the opinions of experts/researchers, through which the framework is designed based on broad common issues” [
57]. This is exactly what is needed to carry out sustainable human development planning, monitoring and evaluation tasks on a global and national scale.
The indirect measurement method also allows minimizing potential discussion of one’s or another country’s national priorities and interests within the scope of the SDGs, targets and indicators. The core dimensions of Agenda 2030—economic, social (i.e., life and education) and environmental—are important for any country and society.
Overall, it shows that the indirect measurement of sustainable human development offers a much wider perspective. We selected the indirect measurement method for creation of the methodology and measurement tool, the AHDI.