This article presents a bibliometric analysis of papers that have measured the efficiency of public education expenditure adopting parametric and non-parametric methodologies. The focus on the analysis of the efficiency of public spending is derived from the scarcity of public resources and the mounting pressure on governments to improve their allocation. Offering more public services with lower levels of public expenditure is an ongoing challenge for many countries, and only a few papers focus on government spending efficiency in the case of emerging countries, although they urgently need to better assign their limited resources allocated to education. This article is a guide for future researchers on this important topic, and it contributes to the literature by exploring the best way to measure efficiency and education performance based on the level of analysis and individual interests. In this sense, this paper makes a first contribution to the literature on bibliometric analysis of education efficiency by focusing on the measurement of different bibliometric indicators as a way to establish how concentrated the literature on this topic is in terms of authors, research centers, journals, and countries. It also investigates publication trends since January 2000 in order to advance the field in emerging and Latin American countries, where the efficiency of public resources has been highly debated but not recently tested.

The innovative element of this paper is that it is the first bibliometric study of articles measuring the efficiency of public education expenditure; thus, it represents a useful tool for future research in the area. As many papers have established, the objective of analyzing the efficiency of public spending is to answer one question: can countries obtain better performance results, in terms of public sectors, using the same resources? This is because public spending represents a key factor in a country’s growth and development (Ouertani et al., 2018)

This study presents three main results:

First, there has been an enormous interest of scholars in the field since 2000, but a decrease in 2015. More specifically, A. Aristovnik and A. Afonso are among the authors with the highest number of publications in the field of efficiency of spending on education.

Second, non-parametric approaches have been the most relevant methodologies in recent years thanks to the development of statistical software, their public access, and the possibility to work with a small database, which allows an easy implementation and use of cross-country comparisons. An indication of this recent focus is the keywords used in the papers, which reveal a strong tendency to implement non-parametric analyses, mainly the Data Envelopment Analysis –DEA- methodology. For example, 78 of the articles found in Scopus (22 %) include DEA, data envelopment analysis, stochastic frontier, or non-parametric as one of their keywords. This is a clear indication of the predominant methodology in the area. Some studies do not have keywords, and others do not indicate, in the abstract or title, the methodology that was used.

Third, there is an evident lack of literature analyzing efficiency of education expenditure in Latin American countries, which opens a future line of research.

This paper is organized as follows: Section 2 presents a brief literature review, Section 3 describes the methodology, Section 4 reports the main results, and, finally, the last part of the document draws conclusions.

Plenty of literature has analyzed the efficiency of public spending, but there is no consensus about the best methodology to use. In education literature, parametric studies use econometric techniques to identify causal relationships between student background, school variables, and educational outcomes. However, most of these studies do not consider the possibility of inefficiency in student, school, or country performance. Thus, recent literature has exhibited an increasing interest in applying frontier methods to evaluate said efficiency using nonparametric techniques such as DEA (Data Envelopment Analysis) and FDH (Free Disposal Hull) (Gnewuch & Wohlrabe, 2018; Papadimitriou & Johnes, 2018). Additionally, some researchers have defended nonparametric approaches based on linear programming because they do not require additional assumptions about the relationship between inputs and outputs, while parametric methodologies rely on the estimation of a parametric frontier function that is usually unknown, i.e., it assumes a determined relationship between inputs and outputs. In this sense, this paper offers a review of the literature in the field in order to identify its trends, mainly regarding methodologies.

Studies that adopt nonparametric approaches have assessed the determinants of schooling quality using cross-country regressions for example, Lee and Barro (2001); Fuchs and Wößmann (2007). The determinants of educational performance include resources allocated to education (such as number of teachers, infrastructure, or amount of public or private expenditure) and parental variables (such as income or educational attainment) (Cordero Ferrera et al., 2015; Emami et al., 2019). In those studies, efficiency is measured based on the error term of the econometric model.

On contrary, non-parametric approaches measure the efficiency of public spending on education by comparing the resources spent with the performance obtained from DEA and FHD analyses (Agasisti, 2014; Kosor et al., 2019).

In 2018, many papers assessed the efficiency of public spending, mainly using nonparametric methodologies. Almost all the studies in that year focused their efficiency analyses on specific country groups, considering similar income levels or even the same regional location because of the difficulty of collecting comparable data in different countries and in order to avoid heterogeneity in the selected sample (Agasisti & Zoido, 2018). For instance, Wolszczak (2017) studied the efficiency of higher education institutions in Europe and the U.S. Afonso et al., (2013) measured the public sector efficiency in Latin America, and Herrera and Pang (2005) did so in developed countries. All the previous studies measured efficiency using a two-stage DEA methodology to estimate the effect that discretional factors (beyond the control of countries, identities or individuals) have on efficiency levels. Aristovnik (2013) and Salazar Cuellar (2014) measured the efficiency of public spending at different levels of education in Latin American and European countries using both DEA and FDH methodologies. Similarly, Afonso and Aubyn (2005; 2006), and Afonso et al., (2005; 2010) analysed the efficiency of public expenditure exclusively in OECD or industrialised countries. Gupta and Verhoeven (2001) analysed the efficiency of 37 African countries.

Other studies have analysed the efficiency of public expenditure using international comparisons without regard to income or regional variables. For instance, Cordero et al., (2018), using a DEA technique, made an international comparison of secondary education efficiency using PISA data. They found greater heterogeneity across countries than across schools. Another important finding is that the existence of tracking or central examinations does not seem to significantly affect the efficiency of secondary schools.

Agasisti and Zoido (2018) evaluated the efficiency of schools in an international setting employing the PISA 2012 database, as well as a DEA technique, and including certain school features, which was their main innovative contribution to the literature. They found that heterogeneity is higher inside countries than between them; therefore, it is more fruitful for a policymaker to compare each school to an international benchmark. Arias Ciro and Torres García (2018) measured the efficiency of public secondary expenditure in developed and developing countries using a two-stage DEA methodology to estimate the effect that discretional factors (beyond the control of countries, identities or individuals) have on efficiency levels.

Finally, to avoid heterogeneity in the sample in terms of wealth and development, some studies have used single-country analyses. For example, Ouertani et al., (2018) measured the relative efficiency of Saudi Arabia’s public spending from 1988 to 2013 using a DEA methodology. In that case, Saudi Arabia could improve their performance in education, health, and infrastructure using the same level of spending; however, education presented the worst performance. They found that the size of government positively affects public spending efficiency, but unemployment and money abroad negatively affect efficiency scores.

Kaur and Bhalla (2018) evaluated the efficiency of government-funded colleges in Punjab, India, using a DEA methodology as a valuable benchmarking tool for these educational institutions. Although they found that colleges are operating at a moderate level of efficiency, some important areas such as infrastructure facility should be improved, as a way to attract or retain more students and monitoring systems.

Gralka (2018) found a persistent inefficiency in higher education in Germany using a new concept related to long-term inefficiency. In the same line, Guccio et al., (2017) assessed the efficiency of Italian public universities adopting a DEA methodology in order to prove the convergence between northern and southern regions; nevertheless, they found that disparities persist between them and the universities have not shown important changes in efficiency levels.

In summary, in the variety of studies mentioned here, there is no consensus about the best methodology to measure efficiency, but the research trend is clearly concentrated on nonparametric techniques. Although De Witte and López-Torres (2017) provide an extensive literature review on education efficiency, they focus on the inputs, outputs, and other factors affecting said efficiency, as well as data sources commonly used in the literature. This paper examines the kind of analyses mentioned before to find recent trends in the literature using different bibliometric indicators.

This bibliometric study examined papers that measure the efficiency of education expenditure through parametric and non-parametric methodologies. As Durieux and Gevenois (2010) established, bibliometrics is a field that uses mathematical and statistical techniques to study publishing and communication patterns in the distribution of information.

Bibliometric studies are essential because there has been an increase in scientific discoveries, and published results are read and quoted by other researchers worldwide. There is an important and growing need to be up to date with recent research and methodologies and be in touch with the knowledge frontier. Therefore, they are useful tools to understand the best way to do something in a specific field.

Bibliometric studies assess databases using different indicators, which aim to determine impact, evolution, state of the art, and trends in a field of knowledge (Sancho, 1990); however, a wide variety of indicators can assess those aspects. As Durieux and Gevenois (2010) claim, there are three types of bibliometric indicators: quantity, quality, and structural. Quantity indicators measure the productivity of a researcher or research center in terms of number of publications in general or in top-ranked journals. The easiest method consists in counting the number of articles published by an author during a certain period of time. Nevertheless, without considering the quality of papers, analysts could make an inappropriate comparison between authors and reach erroneous conclusions in the bibliometric analysis. To overcome this limitation, analysts could use the number of publications in top-ranked journals (selected according to their impact factor) as a better quantity indicator.

Quality indicators measure the relevance or influence of a researcher, journal, or research center based on the impact of their studies on the scientific community. For that purpose, such indicators estimate the number of citations of an author or journal by others. The higher the number of citations, the greater the impact or performance. Authors with many published papers are not necessarily those with the highest impact on the generation of new knowledge. This depends on the type of journal, innovative methodology, dataset, or year of publication.

Currently, many databases could be used to conduct bibliometric analyses, including Google Scholar, Scopus, Econ Lit, and the Web of Science. However, the Web of Science has been the main source of scientific evaluation because it includes publications from all areas of knowledge. Scopus is also a good alternative to the Web of Science because of its advantages (Baier-Fuentes et al., 2018) it contains over 60 million records, most journals indexed in the WoS, and a greater number of exclusive journals compared to the WoS. Additionally, Scopus offers a multidisciplinary database, and it allows users to create filters and search many sources. In this analysis, I used Scopus as the main source to calculate the quantity and quality indicators of this field.

This paper represents a useful tool for analyzing the measurement of the efficiency of spending on education, and it provides summarized results of the leading methodological trends in the literature. The focus of this study is on productivity indicators, such as number of articles per year, author, and journal. As Bonilla et al., (2015) argue, the number of articles is an indicator of productivity and the number of citations is an indicator of influence. Furthermore, another bibliometric indicator used here is the h-index, developed by J.E. Hirsch. It measures the number of works “Y” that have received “Y” or more citations in an “X” set of studies. For example, if an author has an h-index of 10, it means that she or he has 10 papers that have been cited 10 or more times (Bonilla et al., 2015).

The h-index is highly correlated with number of publications and citations, and its main advantage is that it combines a measure of quantity and impact into a single indicator (Costas and Bordons, 2007).

In this work, the search process in Scopus was limited to research published between January 2000 and December 2018 that used the following keywords: public spending, education, efficiency and parametric. After the results were obtained, the studies were selected from four areas: Social Sciences; Economics, Econometrics and Finance; Business, Management and Accounting; and Decision Sciences. The search was not limited in terms of source or document type.

The search equation used here is based on key variables or terms such as public spending, education, efficiency and parametric. The equation is the following:

( ALL ( public AND spending ) AND TITLE-ABS-KEY ( education ) AND TITLE-ABS-KEY ( efficiency ) OR TITLE-ABS-KEY ( parametric ) ) AND ( LIMIT-TO ( SUBJAREA , "SOCI" ) OR LIMIT-TO ( SUBJAREA , "ECON" ) OR LIMIT-TO ( SUBJAREA , "BUSI" ) OR LIMIT-TO ( SUBJAREA , "DECI" ) ).

This equation retrieved a total of 386 results or documents. All the articles included the terms public spending, education, efficiency, and parametric in their title, abstract, or keywords.

These results are sorted by author, journal, publication, country, and information sources using two bibliometric indicators: quantity and quality.

This paper presented a bibliometric analysis of education efficiency, primarily focused on methodological approaches used to rate education performance.

Although research in this field is not concentrated in some authors or journals, it is highly concentrated in developed countries, such as the United States and the United Kingdom, which hold the highest share of scientific publications worldwide. Future studies can assess the efficiency of spending in emerging and developing countries, such as Latin American nations, where the efficiency of public resources has been highly debated but not recently tested. This could be used to ensure that public resources, which are significantly limited, are spent efficiently and identify the policy areas that require more attention. Also it could help to answer the following question: can countries, municipalities, or institutions achieve better performance results using the same resources? Due to the scarcity of public resources and the mounting pressure on governments to improve their allocation, the study and measurement of the efficiency in the use of these resources should lead to new efforts in the agenda of the scientific community.

Moreover, recent research trends have shown the importance of regional and dynamic studies in this field. In the case of Colombia, microdata such as those from standardized tests (e.g., Saber Pro or Saber TyT) could be used in future studies to measure the efficiency of education spending in higher education institutions in Colombia or to compare institutions in the same department using municipalities as units of analysis. Even inside each higher education institution, researchers could be interested in studying the efficiency of resources allotted to each academic program to achieve better results. In those terms, dynamic analysis is needed to make short-, medium-, and long-term goals achievable, which requires the calculation of efficiency indicators year after year as the main input and guidance for university managers to approve budget policies.

Following the latest publication by Barra et al., (2018) concerned with the importance of econometric methodologies to rank universities in Italy, future lines of research can focus on Colombian university rankings and their sensibility to the application of a DEA methodology to measure their efficiency. As Barra establishes, university performance depends on the set of variables under consideration and the methods of analysis employed; therefore, this is an opportunity for researchers to guide university managers to find the most appropriate method for their needs.

Moreover, the easy application of DEA methodologies to measure efficiency represents an enormous incentive to extrapolate studies analyzing efficiency in financial institutions (bank efficiency), where data availability is not a problem, and other problematic policy areas.

This bibliometric study examined papers that measure the efficiency of public education expenditure applying different quantity and quality indicators calculated with information collected from Scopus between January 2000 and December 2018. Two results can be highlighted: (1) this field has attracted many researchers since 2000, and (2) said attraction is related to the use of advanced nonparametric methodologies such as Data Envelopment Analysis. The reason behind the increasing use of this methodology is related to the development of statistical software, its public access, and the possibility to work with a small database, which allows an easy implementation and use of cross-country comparisons.

An interesting result is that, although it is an important topic with a positive research trend (as shown by quantity indicators), academic research is concentrated in industrialized countries and very few European authors. Latin American and emerging countries exhibit an evident lack of studies in this area, which opens up a new line of research.

In terms of the main authors in the field, Levin, Belfield, and Afonso have the highest h-index. In their case, they have at least 20 papers that have received 20 or more citations. Nevertheless, Aristovnik and Afonso achieved the highest level of publication in the area. They have concentrated their analysis in the study of efficiency of public expenditure at different levels (education, health, public sector, etc.) applying a nonparametric methodology.

Studies in the field are mainly published in education and economics journals, such as Education Economics, Economics of Education Review, International Journal of Educational Development, and Econometrica, which are prestigious publications with high impact levels. However, a book has an enormous importance in the topic (i.e., the highest impact level) and represents an essential reading for new researchers in the area: Introduction to Data Envelopment Analysis and its uses: with DEA-solver software and references.

Finally, the variety of bibliometric indicators discussed above confirms that the efficiency of public resources should be evaluated, much more so in education, which is the key driver of economic growth and social wellbeing.