# RECORD 2f1c2029c5f2034d797bc4a5ae390cff3782ab60 # TITLE: Area-Based Hedonic Pricing of Urban Green Amenities in Beijing: A Spatial Piecewise Approach # YEAR: 2024.0 VENUE: Environmental and Resource Economics DOI: 10.1007/s10640-024-00861-2 # AUTHORS: Zhaoyang Liu; Heqing Huang; J. Siikamäki; Jintao Xu # PAGES: 26 CANDIDATE TABLE PAGES (1-based): [17, 18, 19] # ABSTRACT: This study explores a spatial piecewise approach for the hedonic valuation of the area of urban green space at different distances from a property, using a rich census dataset collected from Beijing. We explore three novel empirical strategies that improve the identification of the spatial boundary or threshold distance within which green space is capitalised into housing prices. We first delineated a series of concentric circles surrounding each property and measured the area of green space within each doughnut-shaped ring. We next estimated the hedonic price using three methods. The first is a regression spline model combined with a machine learning type of model selection procedure which objectively selects the exact location of the threshold distance that optimises the model’s predictive performance. The second is a novel matching algorithm that minimises covariate imbalance for a continuous treatment variable (i.e., the area of green space) to provide stronger causal evidence on the hedonic prices of green space at different distances. The third is a spatial difference-in-differences approach that further accounts for endogeneity bias associated with unobserved factors. For our dataset, we found that housing prices are more likely to be affected by green space within a 1 km radius. ===== PAGE 1 (score 6, numeric-paren 0, table-words 0, var-words 6) ===== Vol.:(0123456789) Environmental and Resource Economics (2024) 87:1223–1248 https://doi.org/10.1007/s10640-024-00861-2 1 3 Area‑Based Hedonic Pricing of Urban Green Amenities in Beijing: A Spatial Piecewise Approach Zhaoyang Liu1   · Heqing Huang2 · Juha Siikamäki3 · Jintao Xu2 Accepted: 1 March 2024 / Published online: 25 March 2024 © The Author(s) 2024 Abstract This study explores a spatial piecewise approach for the hedonic valuation of the area of urban green space at different distances from a property, using a rich census dataset col- lected from Beijing. We explore three novel empirical strategies that improve the identi- fication of the spatial boundary or threshold distance within which green space is capital- ised into housing prices. We first delineated a series of concentric circles surrounding each property and measured the area of green space within each doughnut-shaped ring. We next estimated the hedonic price using three methods. The first is a regression spline model combined with a machine learning type of model selection procedure which objectively selects the exact location of the threshold distance that optimises the model’s predictive performance. The second is a novel matching algorithm that minimises covariate imbal- ance for a continuous treatment variable (i.e., the area of green space) to provide stronger causal evidence on the hedonic prices of green space at different distances. The third is a spatial difference-in-differences approach that further accounts for endogeneity bias associ- ated with unobserved factors. For our dataset, we found that housing prices are more likely to be affected by green space within a 1 km radius. Keywords  Urban green space · Hedonic pricing · Regression splines · Model selection · Covariate balancing matching for continuous treatment · Spatial difference-in-differences JEL Classification  Q51 · Q57 · R30 This paper is an output of the Ecosystem Services Accounting for Development project jointly initiated by the Environment for Development Initiative and the Swedish Environmental Protection Agency (SEPA Reference Number: NV-05230-14), and funded by the Swedish International Development Cooperation Agency (SIDA Reference Number: 13/000230). The authors declare that they have no relevant or material financial interests that relate to the research described in this paper. The authors sincerely appreciate the very helpful comments provided by Dr. Jessica Alvsilver, Dr. Christopher Campbell-Duruflé, Dr. Timothy Hamilton, Prof. Nick Hanley, Prof. Thies Lindenthal, Dr. Richard Mulwa, Dr. Matías Piaggio, Dr. Carolin Hoeltken, Dr. Per Stromberg, Dr. Byela Tibesigwa, Dr. Jane Turpie and Dr. Dawit Woubishet. In addition, the authors are greatly indebted to Mrs Cyndi Berck for editing the paper. Last but not least, the authors gratefully acknowledge two anonymous referees and the editor for their very helpful comments on an earlier version of the paper. Extended author information available on the last page of the article ===== PAGE 17 (score 21, numeric-paren 0, table-words 6, var-words 5) ===== 1239 Area‑Based Hedonic Pricing of Urban Green Amenities in Beijing:… 1 3 We estimated four DID regressions (Models 4–7, Table 4), which have the same speci- fication as in Eq. (5) but differ in whether Radiussi is defined as within 1, 2, 3 or 4 km. In Model 4 where the radius is 1 km, the positive and statistically significant coefficient on the interaction term ‘ After × Radius ’ suggests that a new green space tends to increase housing prices within a 1 km radius. In our DID dataset, the average size of green spaces is 4.14ha. This suggests that, approximately speaking, a new hectare of green space increases housing prices in a 1 km radius by CNY 147.82 or USD 22.26 per ­m2 of housing. This is notably higher than the counterpart estimates from the regression spline and matching analyses, although the DID estimate refers to only a subset of the green spaces in the regression spline and matching analyses. In Models 5–7 (where the radius is 2, 3 or 4 km), the coef- ficient on the interaction term ‘ After × Radius ’ is statistically indistinguishable from zero (the lowest p value = 0.49), and the absolute value of the estimated effect is much smaller than that for a 1 km radius. These results provide further evidence that a new green space is more likely to be capitalised into housing prices within a 1 km radius. Our DID approach has controlled for all location- and time-specific factors, in addition to the control variables listed in Table A1. If there are no other confounders, the mean dif- ference in the (residualised) treated and control housing prices would not vary over time before the creation of the green spaces, known as the parallel trends assumption (Wool- dridge 2020). Otherwise, the main causal strength of this DID analysis would be confined to accounting for location-specific time-invariants (both observed and unobserved) at a more detailed level (compared to the regression spline and matching analyses), at the cost of focusing on only a subset of the green spaces in our dataset. Figure A5 in the appen- dix provides some visual evidence for the applicability of the parallel trends assumption in our analysis. A Wald test further corroborates that the mean differences between the treated and control housing prices are statistically equal across the two pre-treatment years (p value = 0.64). These assessments find no evidence that the parallel trends assumption is violated. Table 4   Difference-in-differences estimates Asterisks indicate statistical significance: * p value < 0.10, ** p value < 0.05, *** p value < 0.01. Standard errors are in parentheses DV: log (housing price) Model 4 Model 5 Model 6 Model 7 Radius = 1 km Radius = 2 km Radius = 3 km Radius = 4 km EV After −1.04 × ­10−2* −1.01 × ­10−2* −9.09 × ­10−3 −8.83× ­10−3 (5.35 × ­10−3) (5.47 × ­10−3) (5.73 × ­10−3) (6.52 × ­10−3) Radius −4.13 × ­10−3 −1.01 × ­10−3 1.11 × ­10−2*** 2.22 × ­10−2*** (8.04 × ­10−3) (4.45 × ­10−3) (3.56 × ­10−3) (3.64 × ­10−3) After × Radius 2.31 × ­10−2* 4.62 × ­10−3 −6.58 × ­10−4 −1.11 × ­10−3 (1.23 × ­10−2) (6.73 × ­10−3) (5.38 × ­10−3) (5.57 × ­10−3) Green space location fixed effects Yes Yes Yes Yes Time fixed effects Yes Yes Yes Yes Housing controls (Table A1) Yes Yes Yes Yes Model significance (p value) < 0.01 < 0.01 < 0.01 < 0.01 R2 (within) 0.40 0.40 0.40 0.40 Obs 124,137 124,137 124,137 124,137 ===== PAGE 18 (score 18, numeric-paren 0, table-words 6, var-words 4) ===== 1240 Z. Liu et al. 1 3 3.4  Further Robustness Tests The DID analysis, despite focusing on a subset of the green spaces in our dataset, lends further support to our finding that housing prices are less likely to be affected by green spaces outside a 2 km radius. On the other hand, the spatial distribution of green space in neighbouring locations in Beijing tends to be positively correlated (Wang et al. 2023; Zhang et al. 2021). A location is likely to have more green space if its neighbouring loca- tions have more green space. In fact, for the residential blocks in our dataset, the area of green space within 1 km has a correlation coefficient above 0.60 with the area of green space at 1–2 km, 2–3 km, and 3–4 km. In other words, green space outside a 2 km radius of a property is less likely to directly influence housing price, but tends to be highly correlated with green space within a 1 km radius. This suggests the possibility of instrumenting green space within a 1 km radius using green space outside a 2 km radius, as a means to further explore the implications of potential endogeneity issues. Bayer et al. (2009) adopted a sim- ilar ‘spatial lag’ type of instrument for air quality. To facilitate the instrumental variable (IV) estimation, we first estimated an OLS hedonic pricing regression (Model 8, Table 5). The right-hand side has only one green Table 5   Instrumental variable and placebo estimates Standard errors are in parentheses Asterisks indicate statistical significance: * p value < 0.10, ** p value < 0.05, *** p value < 0.01 DV: log (housing price) Model 8 Model 9 Model 10 Model 11 OLS IV-2SLS OLS OLS Hedonic price Green area 0–1 km 5.90 × ­10−4** 1.40 × ­10−3** 1.05 × ­10−3*** (2.57 × ­10−4) (6.42 × ­10−4) (3.73 × ­10−4) Future green area 0–1 km −3.92 × ­10−4 (1.01 × ­10−3) Housing controls (Table A1) Yes Yes Yes Yes Excluded instruments Green area 2–3 km No Yes No No Green area 3–4 km No Yes No No Weak IV test Cragg–Donald Wald F stat 110.83 (H0: Weak IV) R2 ­(1st stage) 0.50 Over-identification test Sargan statistic: p value ­(H0: Valid IV) 0.19 IV redundancy test LM test: p value ­(H0: Redundant IV) < 0.01 Endogeneity test Diff-in-Sargan–Hansen Statistic: p value 0.17 (H0: Exogenous ‘Green area 0–1 km’) Hedonic price model sig.: p value < 0.01 < 0.01 < 0.01 < 0.01 Hedonic price model R2 0.68 0.68 0.65 0.66 Obs 1270 1270 889 889 ===== PAGE 19 (score 21, numeric-paren 4, table-words 5, var-words 7) ===== 1241 Area‑Based Hedonic Pricing of Urban Green Amenities in Beijing:… 1 3 space variable, which represents the total area of all green space within a 1 km radius, controlling for other housing and location-specific variables listed in Table A1. The OLS estimate of the hedonic price (the estimate for ‘Green area 0–1 km’ in Model 8 in Table 5) is smaller than that derived from the regression spline approach (Model 1 in Table 2), but remains statistically significant at the 5% level. In Model 9, ‘Green area 0–1 km’ is instru- mented using the area of green space at 2–3 km and 3–4 km. The F statistic from the weak IV test (110.83) is markedly greater than the conventional rule of thumb (10) and exceeds a more recently recommended threshold (104.7) (Lee et al. 2022), which provides evidence against the null hypothesis of weak identification. The p value from the over-identification test is well above the critical value (0.10), which further justifies the validity of the instru- ments. Although the p value from the endogeneity test does not reject the null hypothesis of no endogeneity bias at the conventional critical level (0.10), the IV estimate for ‘Green area 0–1 km’ is notably higher than the OLS and regression spline estimates. This suggests that the OLS and regression spline estimates are likely to be conservative estimates of the true hedonic price of green space. Lastly, we undertook placebo tests to further assess whether the foregoing analyses have picked up some distance-dependent patterns other than the effects of green space on hous- ing prices. For each residential block, we measured the total area of green space at differ- ent distances that was created after the residential block was sold. In theory, such ‘future’ green space is less likely to affect housing prices, compared to preexisting green space. We next re-estimated Model 8 after replacing the variable ‘Green area 0–1 km’ (green space inside 1  km that existed before housing transactions) with ‘Future green area 0–1  km’ (green space inside 1 km that was created after housing transactions), to test whether the model would falsely attribute any unexpected effect to future green space. As in Model 10 in Table 5, the estimate on ‘Future green area 0–1 km’ is statistically insignificant (p value = 0.70), which is in line with intuition. Note that this placebo analysis is confined to housing transactions that happened before 2014, because our green space data were col- lected in 2014, and thus do not include any future green space for housing transactions from 2014 onward. We thus re-estimated Model 8 using housing transactions before 2014 to test whether the estimates could be affected by dropping subsequent housing transac- tions. This gave rise to Model 11, where the estimate on ‘Green area 0–1 km’ remains positive and statistically significant, although larger in size compared to the estimate for the full sample. Moreover, we performed another placebo test by adding to Model 10 the area of future green space at 1–2 km, 2–3 km, 3–4 km and 4–5 km. As can be seen in Figure A6 in the appendix, all these placebo estimates are statistically insignificant; the lowest p value is above 0.35. In comparison, the non-placebo estimates in Figure A6 were derived from an expanded version of Model 11, which contains preexisting green space at different dis- tances; here, the estimate on ‘Green area 0–1 km’ is almost identical to that in Model 11. 4  Aggregate Hedonic Prices of Green Space in Central Beijing This section derives the aggregate hedonic prices of green space using the unit hedonic price estimates from Sect. III. To reduce computational workloads, we confined the analy- sis to green spaces that are larger than 0.5ha and located in Beijing’s six central districts. For each of these green spaces, we first searched in our dataset for all residential blocks located in the green space’s 1 km radius. The aggregate hedonic price was then calculated by multiplying the unit hedonic price (the coefficient on the variable ‘Green area 0–1 km’ ===== PAGE 20 (score 4, numeric-paren 0, table-words 0, var-words 4) ===== 1242 Z. Liu et al. 1 3 after being converted from a semi-elasticity estimate to a monetary marginal effect esti- mate) by the total area of the green space and the total floor area of the residential blocks within the green space’s 1 km radius. As an example, Fig. 6 maps the aggregate hedonic prices of these green spaces individually (based on the regression spline estimate in Model (1). Admittedly, owing to the nature of the hedonic approach, the spatial distribution of the Fig. 6   Hedonic prices (billion CNY in 2016 prices) of green spaces in Central Beijing Fig. 7   Aggregate hedonic prices (in 2016 prices) of green spaces in Central Beijing. Note: M1: Model 1, regression spline; M2: Model 2, parametric covariate balancing generalised propen- sity score (CBGPS) matching; M3: Model 3, non-parametric CBGPS matching; M4: Model 4, difference-in-differences (sub- sample); M8: Model 8, ordinary least squares (OLS); M9: Model 9, instrumental variable; M11: Model 11, OLS (sub-sample)