## 4 Data and Methodology
### Dependent and Independent Variable  
The questionnaire has 14 sections, among which the most essential ones for this analysis are sections on _public-sector contracts and innovation_ and _innovations with environmental benefits_. This section was first included in 2014, because of which panel data analysis cannot be considered in this study. Participation in public procurement (PUBPRO) is measured based on the yes-or-no question \"during the three years 2012 to 2014, did your enterprise have any contracts to provide goods or services for domestic public sector organizations or foreign public sector organizations?\" (Table 1). The public sector here refers to government-owned organizations and government providers of services such as energy, security, housing, transport, etc. [58]. \begin{table}
\begin{tabular}{l l} \hline \hline
**Questions and Definitions of Variables** & **Variable Name** \\ \hline \multicolumn{2}{l}{**“During the three years 2012 to 2014, did your enterprise have any contracts to provide goods**} & **PUBPRO** \\ \multicolumn{2}{l}{**or services for:”**} \\ \hline Domestic public-sector organizations & PUBDOM \\ Foreign public-sector organizations & PUBPOR \\ \hline \multicolumn{2}{l}{**“During the three years 2012 to 2014, did your enterprise introduce a product (good or**} \\ \multicolumn{2}{l}{**service), process, organizational or marketing innovation with any of the following**} & **ECOIMP** \\ \multicolumn{2}{l}{**environmental benefits?”**} & \\ \hline \multicolumn{2}{l}{_(1) Environmental benefits obtained within your enterprise_} & _ECOIMP-within_ \\ \hline Reduced material or water use per unit of output & ECOMAT \\ Reduced energy use or CO\({}_{2}\) ’footprint’ (reduce total CO\({}_{2}\) production) & ECOENO \\ Reduced air, water, noise, or soil pollution & ECOPOL \\ Replaced a share of materials with less polluting or hazardous substitutes & ECOSUB \\ Replaced a share of fossil energy with renewable energy sources & ECOREP \\ Recycled waste, water, or materials for own use or sale & ECOREC \\ \hline \multicolumn{2}{l}{_(2) Environmental benefits obtained during the consumption or use of a good or service by the end user_} & _ECOIMP-end_ \\ \hline Reduced energy use or CO\({}_{2}\) ’footprint’ & ECOENU \\ Reduced air, water, noise, or soil pollution & ECOPOS \\ Facilitated recycling of products after use & ECOREA \\ Extended product life through longer-lasting, more durable products & ECOEXT \\ \hline \multicolumn{2}{l}{**“Were any of these environmental benefits due to the following types of your enterprise’s**} & **ECCCAT** \\ \multicolumn{2}{l}{**innovations?”**} & \\ \hline Product (goods or services) innovations & ECOPRD \\ Process innovations & ECOPRC \\ Organizational innovations & ECORG \\ Marketing innovations & ECOMKT \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Sub-questions for public procurement and innovations with environmental benefits. There exist several synonymous terms for eco-innovation, including green innovation and environmental innovation. For a broader connotation, scholars use sustainable innovation by including social concerns. In the survey, eco-innovation was expressed as \"innovation with environmental benefits\", and the following definition was used. According to explicit survey questions, innovations related to recycling fell under the agenda of \"circular innovation studies\" [59]. \"An innovation with environmental benefits is a new or significantly improved product (good or service), process, organizational method or marketing method that creates environmental benefits compared to alternatives. The environmental benefits can be the primary objective of the innovation or a by-product of other objectives. The environmental benefits of an innovation can occur during the production of a good or service, or during its consumption or use by the end user of a product.