e-Government adoption model based on theory of planned behavior: Empirical validation Sevgi Ozkan ⁎, Irfan Emrah Kanat Informatics Institute, Middle East Technical University, Ankara,Turkey a b s t r a c t a r t i c l e i n f o Available online 16 August 2011 Keywords: e-Government Citizen adoption Adoption models Structural equation modeling Partial least squares path modeling The e-Government phenomenon has become more important with the ever increasing number of implementations worldwide. A model explaining the e-Government adoption and the related measurement instrument – a survey – had been developed and validated in this study. In a post Technology Acceptance Model (TAM) approach, theory of planned behavior (TPB) was extended to fitthe requirements ofe- Governmentcontext.The adoption of student loans service ofthe higher education studentloans and accommodation association of Turkey (KYK) was investigated to obtain data for empirical validation.The instrument was administered to over four-hundred students and partial least squares path modeling was employed to analyze the data. The results indicate that the model was an improvement over TAM in terms o predictive power. The constructs trust, perceived behavioral control and attitudes successfully explained th intention to use an e-Government service. The findings presented in this study provide useful insights for researchers and policy makers when dealing with e-Government services. © 2011 Elsevier Inc. All rights reserved. 1. Introduction The application ofinformation technologies (IT) to government services has given rise to e-Government.e-Governmentprovides several benefits in terms of efficiency, availability, costs, and return on investments (Organisation for Economic Cooperation and Develop- ment [OECD],2007; United Nations Departmentof Economic and Social Affairs [UNDESA], 2008,2010 ). As these benefits have become more apparent,the number of countries employing e-Government services began to increase, such that among the 192 countries surveyed in the UN e-Government survey there was not one country that did not employ some form of e-Government (UNDESA,2008, 2010). The financial reports also support these findings. This worldwide trend is also evident in Turkey where expenditures on e-Governmenthave been steadily rising since 2001 (OECD, 2007; UNDESA, 2010). The expected returns on investment (ROI) for e-Government projects are extremely high. For example,the estimated investment for an e-Government project in social insurance association of Turkey (SSK) was 2.4 million TL whereas the estimated return on the same project was 1.8 billion TL (OECD, 2007). But these ROI values can only be actualized if the projects are successful. Unfortunately, the success rates have been reported to be low. Studies conducted in Manchester University, UK found out that only 15% of the e-Government projects achieved all of their established goals(Heeks, 2008). The main determinant ofsuccess for G2C services is the utilization ofthese services.The utilization of services is a measure of adoption of the service by citizens. UN report lists the reasons behind low adoption of e-Government services as: Usefulness, Content Accessibility, Lack of Trust,Lack of Confidentiality, Socialand Cultural Issues, Inadequate Infrastructure, Inadequate Delivery of Services (UNDESA, 2008). The reasons listed above have also been noted in the e- Government adoption literature. The usability and accessibility have long been known to influence the adoption of technological artifacts (Davis,1989).The uncertainty in online interactions is known to be lessened by trust and the role of trust and confidentiality in on-line interactions has been a subject well studied (Gefen,Karahanna,& Straub,2003; McKnight,Choudhury,& Kacmar,2002).International nature of this phenomenon had caused social and cultural issues and unique infrastructural differences among the countries to be inves- tigated (Carter & Weerakkody, 2008). Considering the significant amount of resourcesspent on e- Governmentprojects,each failed project means that a significant amount of taxpayer money has been wasted. e-Government adoption models can identify the factors leading to adoption by citizens, which could then lead to more successful e-Government projects. The aim of this study is to develop and validate an e-Government adoption model for predicting and explaining citizens' adoption behavior regarding the use of government to citizen (G2C) e- Government Information Quarterly 28 (2011) 503–513 ⁎ Corresponding author at: Informatics Institute, Middle East Technical University, Ankara,Turkey.Fax: +90 3122103745. E-mail addresses: sevgi.ozkan@brunel.ac.uk, sozkan@ii.metu.edu.tr, sevgiozkan2005@hotmail.com (S. Ozkan). 0740-624X/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.giq.2010.10.007 Contents lists available at ScienceDirect Government Information Quarterly j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / g ov i n f