**Table 5.** DEA analysis.



**Table 5.** *Cont.*

**Figure 5.** DEA results.

Taking into account the generation of waste, recycling rate of all waste, recycling rate of e-waste, circular material uses rate, and the value added, Croatia, Netherlands, Luxembourg, Slovenia, Belgium, Denmark, Ireland are the leaders among EU countries. The lowest performers, Greece and Romania, reach slightly over 50% efficiency.

The concept of technological competitors was used to group the countries (listed in Table 5), which is illustrated in Figure 6 with an additional indication of the direction of dependences.

**Figure 6.** The competition of effective objects graph. The first graph (**a**) gathers competitors in the group of 100% efficient states. The next one presents the countries that may switch places with slight changes in data. The groups are as follows: (**b**) Estonia France, Cyprus Hungary, Austria, Italy Bulgaria, France Hungary, Lithuania; (**c**) Germany, Malta, Poland, Spain, Sweden, Czechia, Finland; (**d**) Portugal, Slovakia Latvia; € Romania, Greece. Designated groups connect countries with similar effectiveness. Group (**b**) includes countries with efficiency from 80.00% to 98.60%; group (**c**) from 70.08% to 88.70%; group (**d**) includes countries from 73.90% to 77.70%; group (**e**) consists of countries with a score slightly above 51%. The grouping allowed for the identification of similar countries that are in a sense dependent on each other in terms of the final assessment. After excluding 100% effective ones, changes in the characteristics of countries within the groups would affect the score of the remaining ones.

## **6. Discussion of Results**

Over the past few years, the concept of the circular economy gained increasing attention around the world as a way to counteract climate change and save resources. A CE could help overcome pressures on resources arising from the estimated growth of the global population. It is hoped that transition to a CE would result in new economic opportunities [155], new jobs (in terms of type and numbers), higher productivity [156], and the improved quality of life for all thanks to the environmental recovery, health benefits, and less pressure on land and Earth's resources.

The necessity to change the economic model and to decouple growth from resource consumption is of interest not only to politicians, but also to average European citizens. As research results indicate, most Europeans believe that environmental protection is very important to them personally [157].

Whereas the general interest in the CE is well reflected in the bulk of scientific publications, the specific issue of measuring the performance of countries in achieving a CE aims is not yet sufficiently grounded in the literature. This paper is a contribution to the discussion on CE metrics and measurement. It presents a methodology of an objectivised comparative assessment of the degree of implementation of CE principles in the EU member states. The proposed approach is based on the DEA method supported by factor analysis. Circular Economy Indicators published by the European Statistical Office (Eurostat) [158] served as the input data.

The conducted calculations and the analyses performed on their basis suggest that the position of a particular country in achieving the CE aims is strongly correlated with its GDP per capita. The fact that richer economies are more advanced in achieving CE aims may indirectly imply that the implementation of CE principles requires investments and expenditures that poorer countries are unable to bear. Apparently, transition towards the CE requires costly modern technology, perpetual knowledge generation, and advanced infrastructures [23].

Factor analysis shows that many CE indicators are strongly correlated with each other and may be aggregated into meta-indicators (factors) and represented by one indicator that displays the strongest correlation with a given meta-indicator. In this situation, it is reasonable to limit the number of CE indicators, which will simplify the CE statistics and the assessment of countries' standing in achieving CE goals.

Comparative performance assessment of the EU member states allows for splitting them into three groups of countries with a similar relative efficiency in the CE goals' implementation: (90%, 130%), (70–90%), (50–70%). This shows a certain stratification within the EU when it comes to CE goals' implementation.

Thanks to the competition graphs, it is possible to indicate optimal technologies (i.e., CE indicator values) of technological competitors of particular countries so that they achieve the results at least equal to the one of the reference country.

Limitations of this approach should also be pointed out. Firstly, the obtained country ranking depends directly on the chosen evaluation criteria. Therefore, it is important that the adopted indicators are well justified on scientific grounds and are reflective of the key aspects of CE. Secondly, with 27 countries under evaluation, the number of assessment criteria should not exceed the 6–9 range. Such limitation requires a significant decrease in the number of indicators chosen from the list of the UE Circular Economy Indicators. DEA analysis results are sensitive to the choice of input and output variables. Therefore, the CE indicators should be selected diligently, and various combinations of variables should be tested for stability of results [159]. Thirdly, results obtained with DEA may be sensitive to outliers; hence, the data should undergo preliminary screening with regards to their homogeneity. Fourthly, one should keep in mind that the results change in time; thus, the static assessment of particular countries at a given point in time should be complemented with the dynamic evaluation of the change of their performance in time.

The indicated limitations are a good guidance as far as possible future research directions are concerned. The authors intend to examine the sensitivity of various combinations

of CE indicators included in the country assessment, carry out simulations to evaluate the impact of outliers on the result stability, and look into the changes in CE performance of particular countries over a certain period of time.

Some policy implications may be derived from the study results. The objectivity and scalability of the DEA approach to the evaluation of CE implementation make it a suitable approach to comparing the effectiveness of CE policy packages [78] beyond the European Union. For example, benchmarking of OECD or G20 countries [160] with the use of the proposed approach is feasible. Such an internationally adoptable comparison tool will be necessary when the CE attains the status of a global policy [161,162]. Moreover, the CE agenda should not be used as an instrument of a disguised domination perpetrated by the richer countries with the aim of preserving their competitive advantage. The CE policy must not create winners and losers [163].
