## 3 Theoretical Framework
We therefore used insights from the field of HRM to examine how context factors could affect the performance of public procurers with regard to SPP. Within the HRM field, the AMO framework of [PERSON] [48] is frequently used. It identifies ability, motivation, and opportunity as determinants of employee performance [48]. The AMO framework has been tested in numerous studies and shows that a well-trained and skilled employee will be able perform better and that a motivated worker will be willing to \"go the extra mile\", but that if the work environment does not provide adequate opportunities the employees' abilities and motivation will be meaningless [49]. In short, employees have to be able, motivated and have the opportunity to actually do something; if they do not then it becomes incredibly hard to do it. We assume a similar mechanism can be found in the implementation of sustainable public procurement. In this research, we will therefore use the AMO framework to research the impact of procurers' abilities, motivation and opportunities on the implementation of various types of SPP. Ability is operationalised in this study as the skills and knowledge that procurers perceive to have about sustainability. Sustainability in general and SPP in particular are considered complex concepts, requiring specific knowledge and skills. Both knowledge and skills have been identified as important drivers or conditions for the implementation of SPP and particularly GPP [9; 10; 50; 51]. Knowledge of SPP practices has thus already been found to play an important role in the implementation of GPP [9], but whether this also applies for the other types of SPP and if the same holds true for skills related to SPP is not yet known. Skills have been mentioned as being important for the implementation of SPP, but their impact has not yet been tested. The first hypotheses are therefore:  
**Hypothesis 1 (H1)**. : _Knowledge about sustainability and SPP has a positive effect on the implementation of all types of SPP._  
**Hypothesis 2 (H2)**. : _Skills related to sustainability and SPP have a positive effect on the implementation of all types of SPP._  
Motivation is operationalised in this research as affective commitment to SPP. Several studies indicate that if procurers are motivated or committed to implement a SPP policy, they are more likely to implement it [37; 53; 52]. Affective commitment to SPP refers to the desire to show support for SPP based on an inherent belief in the benefits of SPP, and thus not out of peer pressure or fear of repercussions [9; 10; 11]. It has already been positively linked to the implementation of GPP [9; 10; 11], but has not yet been examined in relationship to other types of SPP. The third hypothesis is therefore:  
**Hypothesis 3 (H3). **_Affective commitment to SPP has a positive effect on the implementation of all types of SPP._  
Opportunity refers to the opportunity a procurer has to include SPP in their procurement projects. As stated earlier, the procurement process is a decision-making process where the decisions of the procurer to, for example, look up additional information about sustainability can result in more SPP [9; 10]. However, they have to be in an environment that is conducive to searching for more information and that is open to doing something with the results. Procurers therefore have to work in an organisation that is open to new ideas and to learning something new. [PERSON] and [PERSON] [8], for example, found that the degree to which the prevailing climate in an organisation is supportive of change affects the development of sustainable procurement. Opportunity has therefore been operationalised as the organisational learning capacity. The organisational learning capability consists of the organisational and managerial characteristics that foster the organisational propensity to learn, and it encompasses five dimensions: experimentation, risk taking, interaction with the external environment, dialogue, and participative decision-making [54].