analyse the metadata structure, how the data is harvested, and how this portal aligns with other EU activities. The authors then proceed to provide an insight on the portal’s sustainability issues, such as an increasing amount of datasets and data providers, and the change of governmental institutions (resulting in a shifting of responsibilities). To conclude, the authors identify a number of challenges for portals such ashttp://GovData.de.
The aim of the authors of [90] was to find the limits and challenges of Brazilian anti-corruption and transparency portals through reviewing the existing literature. After assessing the existing literature, Matheus et al. compare the findings based on Web 2.0 usage and new Information and Communication Technologies (ICTs). The authors proceed to discuss the limits and challenges of the portals in question, and give recommendations towards avoiding and/or solving them. A specific limitation that the authors encountered is that most portals consider transparency to be limited to offering data to the consumers, without proceeding to provide help for its consumption.
In [153] a description of the key functionalities of open data portals is presented. Ubaldi uses http://PublicData.eu as an example throughout the publication. The author identifies two essential factors required for opening governmental data; namely discoverability and good quality data.
Regarding the former factor, the author points out the importance of data catalogues, and also the lacking efforts with regard to cross-language searching of open datasets.
Zuiderwijk et al [162] propose a framework of 35 functionalities for comparing open data infrastruc-tures and consequently compare three different open data infrastrucinfrastruc-tures. The authors focus on the functionality of the infrastructures, rather than on the quality of the provided data or other requirements such as reliability and scalability. They concentrate on the requirements for the open data process, such as the creation, publication, finding, use, and linkage. The authors hence identify various differences within the assessed infrastructures, but also note that none of the infrastructures supports all aspects of the open data process.
Another popular approach was to evaluate the features provided in data portals and their usability, such as the number of data formats available and multilinguality. The authors of [46] and [77] both evaluate, for different use-cases, how portals and catalogues actually enable the use, re-use, and distribution of data. They identify shortcomings such as consumers’ difficulty in identifying the required datasets and the use of different formats.
Liu et al. [77] analyse a number of Australian catalogues that provide sustainability-related data with the aim of investigating a Linked Data approach for supporting sustainability researchers in their efforts to create and investigate sustainability science hypotheses. The authors observe that different government entities may contribute to the same field of data from different perspectives. Thus it would be difficult for data consumers to quickly and easily identify the most useful dataset for their use-case unless they know the responsibility of each entity who published the dataset. Another observation is that different government entities publish their data in different formats. This results in extra efforts required to convert the datasets into one format, if even possible.
Similar to the above, González et al. [46] focus on Mexican open government data implementations.
The authors focus on both the demand and supply side of open data and note that while the law mandating governments to open their data has been in force for ten years, there are still various challenges to achieve the true potential of open government data.
In [45], Fuentes-Enriquez and Rojas-Romero research the use of mobile applications in Mexico by all stakeholders of open government data. They report that the involved entities have an active participation in the creation of government mobile applications. The authors also explore a number of applications developed by different stakeholders, including the government, private organisations, and also citizens, and identify their contribution in allowing the stakeholders to actively participate in governance processes.
A similar research is carried out by Sandoval-Almazan et al. in [125], where the authors analyse the use
3.2 Open Government Initiative Evaluations
of open data and mobile applications in a number of countries.
In [126], Sayogo et al. carry out a preliminary exploration of the worldwide status of open government.
The authors analyse open government data portals from 35 countries, reviewing the published data, the provided features, and the level of stakeholder participation. They also provide a framework for assessing open government data initiatives. The authors of [114] and [118] also evaluate the status of open government initiatives, however, they directly focus on the Colombian government initiative as a whole, rather than for specific portals. Similarly, the authors of [36] and [89] both discuss the current state of Brazilian open data initiatives. The authors of [76] and [156] both lead out a study on the Taiwanese open data platforms with the aim of identifying their status. The Greek open data movement is analysed in [1], where the authors analyse the current state of open data from three different perspectives, namely the functionality, the semantics of the data, and the provided features.
The authors of [42], in a somewhat non-traditional evaluation, attempt to analyse the relationship between the open data ambitions at the European level and those at the Austrian federal level (focusing mostly on Vienna), both from the data consumer and producer side. The led study attempts to identify to what extent developments at the EU level influence Austrian practices with regard to open data initiatives.
The authors, Egger-Peitler and Polzer, point out that the efforts within Vienna are mostly decoupled from EU strategies.
The authors of [87] analyse the http://PublicData.eu catalogue and assess the metadata recorded for each dataset within it. The objectives behind this study are twofold: firstly to identify the quality of a sample of metadata properties and secondly to study the stated level of data openness. The authors use Tim Berners-Lee’s Five Star Scheme for Linked Open Data as an evaluation scale, and assess the data format, licences, and level of openness.
In publication [104] a number of Italian Municipalities’ portals are evaluated with the aim of under-standing the link between the Open Government Data legislation and a newly enacted Transparency Act.
Palmirani et al. theorise that the latter does not enable and enhance open government data. After the led evaluation the authors conclude that the Transparency Act has affected badly the quality of the published datasets, as it is only oriented towards reducing corruption, rather then enabling open government data as a means to that end.
Publications [37,63,105,146] all assess stakeholders’ opinion to a certain degree. Through interviews and online polls, the authors of [105] identify a number of factors that enabled the success of the open government data strategy in Vienna. The authors of [37] and [146] discuss issues and challenges of developing applications that implement open government data. While the former extract these challenges from evaluating and analysing an application developed during an organised hackathon, the latter describe the challenges they faced during the development of their own application. Finally, the authors of [63]
analyse the interpretations and perspectives of stakeholders with regard to opening municipalities’ data in Sweden, and strive to identify how the stakeholders’ opinion contributes to the implementation success of open data initiatives.
Petychakis et al. [108] do not focus on a single aspect for their evaluation. Rather, the authors carry out a comprehensive analysis of open government data initiatives in the European Union, focusing on functions, data semantics, and features. They collect and categorise a number of public data sources for each European Union member country, and they assess their characteristics and provided services. The authors identify the differences in content, licences, multilinguality, data accessibility, data provision, and data format. Finally, the authors point out that while the quality of open government infrastructures is improving, there are still great differences between national open data portals. Petychakis et al.
also identify two important challenges which are still not catered for, namely multilinguality and open licences. In a similar but downscaled manner to [108], the authors of [123] compare three South American open government data initiatives (Brazil, Colombia, Chile), however, the authors rather focus on open
government policies, citizen involvement and the use of new technologies.