## 3 Analysis
### Green Purchasing Rate by Category
The colors are the same as in Figure 3; for example, the blue areas represent the share of the municipalities whose green purchasing rate for the given category is almost 100%, and the blue, orange, gray, and yellow areas in Figure 4 jointly show the share of municipalities measuring their green purchasing rate for each category. The categories are sorted in descending order according to share. The average share across the categories is 24%. Thus, it is clear that many municipalities do not measure their purchasing rates. From Figure 4, we can see that the share of municipalities measuring their green purchasing rates varies widely by category. Sixty-four percent of municipalities measure their green purchasing rate for paper products, whereas only 9% of them measure their green purchasing rate for other equipment. As the average share of municipalities measuring green purchasing rates is only 24%, it can be seen that the green purchasing rate for paper products is much easier to measure than the rates for other categories. Stationery and cars are also easier to measure (44% and 42%, respectively). It is likely easy to judge whether products in these categories are green products because there are many eco-labeled products in the categories or clear environmental criteria for products in the categories. As a general trend, more municipalities measure the purchasing rate of the categories for which more municipalities implement green purchasing. While 50% of municipalities implement green purchasing in public works (from Figure 3), only 12% of those municipalities measure their green purchasing rate for public works. This tendency is similar to findings in the literature. [PERSON] et al. (2018) reported that it is hard to judge whether or not construction contracts fulfill the environmental requirements in the case of Sweden. [PERSON] and [PERSON] and [PERSON] (2018) also provided evidence that there are some difficulties with assessing the tenderers of architectural and engineering services using the environmental criteria in Swedish municipalities. Japanese municipalities may be in the same situation. The main reason for this is likely that it is hard to judge whether some public work products meet the criteria for being a green product, but it is easy to judge whether other public work products do. Some public work products are tailor made rather than ready made. Therefore, it is hard to judge whether they meet the criteria. However, it is relatively easy to judge whether certain public work products, such as road paving, meet the criteria for being green products ([PERSON], 2018). We suspect that many municipalities implement green purchasing for products in public works categories with clear criteria for green products, but they do not know whether they are implementing green purchasing for products with unclear criteria. As a result, many municipalities implement green purchasing for public works but do not measure the purchasing rate of the categories. In this subsection, we compared categories in terms of implementation of green purchasing and measurement of green purchasing rate. In discussing the comparative results, we discussed the following three aspects of the implementation and measurement: (1) frequency (quantity) of purchases, (2) product/services features (tailor made products or ready made products and existence of clear criteria such as eco-labels), and (3) whether it is easy to purchase in bulk (by the procurement department). While (1) and (2) are not controllable/easily controlled by municipal initiatives, (3) can be controlled by municipal initiatives. In addition, (1) and (2) make it easier to implement green purchasing, but whether they make it easier to measure the green purchasing rate is unclear. With regard to (1), in particular, the learning effect is likely to make it easier to implement green purchasing as the frequency of purchases increases.