# RECORD b8c37b8ea0a12e9cbed953c9880d16a2673b2159 # TITLE: Measures of labour market accessibility. What can we learn from observed commuting patterns? # YEAR: 2020.0 VENUE: nan DOI: 10.18335/region.v7i1.261 # AUTHORS: Liv Osland; Arnstein Gjestland; I. Thorsen # PAGES: 22 CANDIDATE TABLE PAGES (1-based): [13, 17, 22] # ABSTRACT: It is well known that measures of labour market accessibility explains spatial variation in housing prices even in markets with polycentric labour market structures. This paper examines whether data on observed commuting patterns can replace or supplement gravity-based measures representing the commuting potential at specific locations. We use data from a region in Western Norway,and we find that measures based on observed commuting flows and commuting time cannot replace a gravity-based measure of labour market accessibility. Based on, inter alia, the spatial Durbin estimator we find that measures of observed commuting flows increase the explanatory power of a hedonic house price model. ===== PAGE 1 (score 7, numeric-paren 0, table-words 0, var-words 7) ===== Volume 7, Number 1, 2020, 49–70 journal homepage: region.ersa.org DOI: 10.18335/region.v7i1.261 Measures of labour market accessibility. What can we learn from observed commuting patterns?∗ Arnstein Gjestland1, Liv Osland1 and Inge Thorsen1 1 Western Norway University of Applied Sciences Received: 13 February 2019/Accepted: 28 February 2020 Abstract. It is well known that measures of labour market accessibility explain spatial variation in housing prices, even in markets with polycentric labour market structures. This paper examines whether data on observed commuting patterns can replace or supplement gravity-based measures representing the commuting potential at specific locations. We use data from a region in Western Norway, and we find that measures based on observed commuting flows and commuting time cannot replace a gravity-based measure of labour market accessibility. Based on, inter alia, the spatial Durbin estimator we find that measures of observed commuting flows increase the explanatory power of a hedonic house price model. 1 Introduction The relationship between house prices and access to workplaces is a central theme in both theoretical and empirical housing market research. There are many reasons why this relationship is important. Travelling to work is a regular and bounded trip. According to V˚agane et al. (2011), travelling to work constitutes 18 per cent of all travels in Norway. During workdays, approximately 25 per cent of the travels are journey to work. Most commuters travel at the same point in time every day, which also creates congestion. Road transportation infrastructure is often given a capacity to deal with such traffic peaks. At the same time, investments in the road network affect labour market accessibility, which is in turn capitalized into house prices. In order to reduce many of the transportation problems related to commuting, planners may seek to locate houses in areas where job accessibility is assumed to be high. According to Handy, Niemeier (1997), there is no consensus in the literature on a good measure of accessibility. In explaining housing prices, gravity-based accessibility measures have been suggested as a generalization of modern polycentric labour market structures. Although more recent research has shown that gravity-based accessibility measures explain significant spatial variation in housing prices, Handy, Niemeier (1997) show that the gravity-based measures are not the only weighted measures that can be used to capture the job opportunity density of a given area. Gravity-based measures of labour market accessibility reflect the potential for commut- ing from a specific residential area. In this paper we introduce three other measures, based on actual commuting patterns. One measure is origin specific: the percentage of the total working population living in the zone and working in a different zone. The second measure ∗We are grateful to two anonymous reviewers for very helpful comments. 49 ===== PAGE 13 (score 100, numeric-paren 67, table-words 4, var-words 2) ===== A. Gjestland, L. Osland, I. Thorsen 61 Table 2: Estimated results from alternative hedonic house price models Variable name M0 M1 M2 M3 M4 M5 Constant 12.970 12.417 12.942 12.085 12.543 11.430 (71.89) (63.52) (71.75) (59.50) (49.53) (38.87) LotSize -0.173 -0.204 -0.167 -0.203 -0.177 -0.221 (-3.00) (-3.62) (-2.91) (-3.55) (-3.1) (-3.92) LotSize2 0.022 0.025 0.022 0.025 0.023 0.026 (4.62) (5.27) (4.55) (5.22) ( 4.72) (5.59) RurLotSize -0.025 -0.021 -0.027 -0.023 -0.025 -0.019 (-10.28) (-8.83) (-10.15) (-9.64) (-10.11) ( -8.36) Age -0.2017 -0.192 -0.205 -0.199 -0.204 -0.196 (-11.75) (-11.38) (-11.84) (-11.72) (-11.75) ( -11.47) Age2 0.017 0.016 0.018 0.017 0.018 0.016 (5.75) (5.23) (5.92) (5.65) (5.85) ( 5.38) Garage 0.042 0.043 0.040 0.042 0.042 0.040 (7.21) (7.44) (6.93) (7.16) (7.19) (7.06) LivingArea 0.510 0.505 0.510 0.503 0.511 0.504 (42.77) (42.69) (42.80) (42.66) ( 42.99) (42.88) YearDum04 0.097 0.098 0.097 0.097 0.097 0.097 (8.89) (9.03) (8.90) (9.05) (8.89) (8.98) YearDum05 0.206 0.207 0.205 0.205 0.205 0.205 (18.75) (18.92) (18.68) (18.90) (18.68) (18.84) YearDum06 0.370 0.371 0.370 0.370 0.370 0.370 (33.55) (33.67) (33.49) (33.82) (33.51) (33.82) YearDum07 0.558 0.558 0.558 0.557 0.558 0.555 (53.95) (54.17) (53.85) (54.44 (53.93) (54.39) DistCBD -0.056 -0.104 -0.043 -0.114 -0.076 -0.171 (-3.14) (-5.36) (-2.28) (-5.57) (-3.90) (-7.40) DistCBD2 -0.046 -0.027 -0.051 -0.024 -0.043 -0.0150 (-13.18) (-5.84) (-12.22) (-4.53) (-10.86) (-2.85) ACCESS 0.064 0.096 0.114 (6.48) (7.79) (7.06) IN-COM -0.030 -0.083 (-2.06) (-4.90) OUT-COM -0.043 0.001 (0.03) (2.31) MCT 0.393 0.399 (2.45) (2.29) MCT2 -0.081 -0.054 (-2.41) (-1.45) n 4392 4392 4392 4392 4392 4392 R2 0.822 0.824 0.823 0.826 0.823 0.826 R2(adj) 0.822 0.824 0.822 0.825 0.822 0.825 Log-likelihood 1184.02 1207.05 1187.48 1226.90 1187.60 1228.14 VIF 16.36 17.56 16.06 17.60 45.87 46.20 Ramsey reset 0.767 0.760 0.464 0.316 0.8003 0.5364 APE 510405 508469 510366 507978 510486 508223 SRMSE 0.289 0.288 0.290 0.288 0.289 0.288 RLM-lag 1.70 0.86 1.38 0.17 1.70 0.39 RLM-error 323.59 313.09 324.15 307.78 320.36 313.01 REGION : Volume 7, Number 1, 2020 ===== PAGE 14 (score 7, numeric-paren 0, table-words 0, var-words 7) ===== 62 A. Gjestland, L. Osland, I. Thorsen Note: The dashed lines refer to M3, while the solid line refers to a corresponding model specification without a gravity-based accessibility measure (M2). Predicted housing prices for variation in OUT-COM based on M2 is not shown in the Figure to the right, given that this variable does not contribute to explain the variation in housing prices in these two models. Figure 3: Predicted house prices of a standard house Note: The solid line refers to M1 where the commuting variables are excluded. The dotted line refers to M3, and the dashed line refers to M5. The values of the accessibility variables is mean-normalized. Figure 4: Predicted house prices of a standard house Figure 6, however, there is a substantial difference between the model M5, and the more parsimonious model M4. Technically, this is due to the different parameter values estimated for the quadratic term, but it can also be argued that the results reflect changes in the characteristics of the urban structure. As pointed out in Section 3, a high MCT may reflect either a peripheral location, or a centrally located area with heterogenous agents and considerable excess commuting. For the model M5, the effects of labour market heterogeneity and a high level of spatial interaction in the central parts of the urban area seem to dominate, since MCT is estimated to have a positive impact on housing prices. Over time, the job growth in the Stavanger urban area has come in areas that used to be the outskirt of the city, mainly in suburban industrial parks. As a consequence, workers living in residential areas close to the city centre, see Figure 1, no longer have on average shorter commuting times than workers living in some of the suburban areas. Still, some of the residential areas close to the city centre have very high housing prices. These areas have traditionally been fashionable residential locations, with neighbourhoods that are popular, beyond the pure urban attraction effect. This is one possible explanation why housing prices are predicted to be an increasing function of MCT. The first, rising part of the curve resulting from model M4 in Figure 6 can be explained from the same line of reasoning as above. In this model, however, the labour market accessibility measure is not incorporated. Since MCT is closely and negatively correlated to labour market accessibility (Pearson’s correlation coefficient is -0.8677), the labour REGION : Volume 7, Number 1, 2020 ===== PAGE 17 (score 84, numeric-paren 62, table-words 1, var-words 2) ===== A. Gjestland, L. Osland, I. Thorsen 65 Table 3: Estimated direct, indirect, and total impact from variants of M3 and M5 using the spatial Durbin Estimator M3 M5 Variable Name Direct Indirect Total Direct Indirect Total Lotsize -0.201 0.150 -0.051 -0.173 0.012 -0.161 (-6.47) (2.21) (-0.70) (-4.92) (0.15) (-1.84) LotSize2 0.025 -0.013 0.013 0.024 -0.005 0.020 (9.69) (-2.20) (2.01) (8.73) (-0.67) (2.64) RurLotsize -0.028 0.007 -0.021 -0.041 0.024 -0.017 (-8.89) (1.76) (-8.10) (-3.92) (2.21) (-5.24) Age -0.196 0.038 -0.158 -0.161 -0.097 -0.285 (-11.93) (1.05) (-4.13) (-9.39) (-2.51) (-6.22) Age2 0.016 -0.004 0.012 0.009 0.020 0.028 (5.89) (-0.71) (1.84) (2.95) (3.09) (4.13) Garage 0.040 0.026 0.066 0.039 0.009 0.048 (6.48) (2.06) (4.70) (6.78) (0.63) (2.86) LivingArea 0.503 -0.037 0.466 0.487 0.094 0.581 (52.91) (-1.84) (21.11) (53.64) (3.72) (20.94) YearDum04 0.099 -0.029 0.070 0.097 -0.001 0.096 (9.58) (-1.24) (2.86) (9.05) (-0.04) (2.22) YearDum05 0.209 -0.027 0.182 0.207 0.038 0.245 (19.93) (-1.16) (7.48) (19.40) (1.03) (5.72) YearDum06 0.373 -0.014 0.359 0.371 -0.019 0.353 (35.41) (-0.57) (14.40) (35.31) (-0.53) (8.50) YearDum07 0.560 -0.022 0.538 0.557 0.001 0.558 (56.92) (-0.92) (21.51) (54.24) (0.04) (14.02) DistCBD -0.081 -0.073 -0.153 -0.036 -0.103 -0.139 (-3.45) (-2.09) (-4.86) (0.40) (-0.97) (-4.23) DistCBD2 -0.024 0.008 -0.016 0.014 -0.033 -0.019 (-4.20) (0.95) (-1.94) (0.37) (-0.87) (-2.66) ACCESS 0.084 0.035 0.120 0.161 -0.051 0.109 (7.23) (1.87) (6.99) (2.00) (-0.63) (5.22) IN-COM -0.073 -0.064 -0.136 (-4.67) (-2.62) (-6.18) OUT-COM 0.040 0.033 0.073 (2.36) (1.87) (2.72) MCT 0.247 -0.122 0.125 (1.80) (-0.88) (3.43) Note: Z-values in parentheses. The spatial Durbin model yields the same sign on all the estimated parameters, as for the ordinary least squares estimator. The direct impacts yield results that are within the 95% confidence region of the ordinary least squares regression results for the model variant based on M3. For the specification based on M5, this is not always the case. For most of these variables the total impact is within the 95% confidence region. The impacts related to age variables is not within the mentioned 95% confidence region. For M1, not reported, the total impact of ACCESS is not within the 95% confidence region. The indirect impact is negative, but not significant. Indirect impacts are significant at the 5% level for the variables LivingArea and Age2 for the model based on M5. The same is the case for the spatial Durbin variant of M1. In the model based on M3, only IN-COM has a significant indirect impact at the 5% significance level. The indirect impact is negative. This means that an increase in IN-COM of the houses neighbouring a house i, will on average have a negative impact on the price of house i. Hence, there are negative spillover effects of having a house located in an area with a high relative level of in-commuting. This result is in line with our interpretations of regression results found in previous sections. The average indirect REGION : Volume 7, Number 1, 2020 ===== PAGE 18 (score 12, numeric-paren 0, table-words 1, var-words 10) ===== 66 A. Gjestland, L. Osland, I. Thorsen impacts of OUT-COM and ACCESS are positive, but not significant at the 5% level. The results of this robustness check also show that all the direct impacts related to the studied variables have the same sign as the ones documented in Table 2. Given the fact that the correlation between the variables are relatively high, it is to be expected that the inclusion and exclusion of variables will have an impact on the value of the estimated coefficients. The direction of any existing bias is not possible to determine based on any of the robustness checks. 7.2 Reverse Causality The second relevant type of endogeneity problem could be reverse causality. By way of example, neighbourhoods with higher housing prices could attract high-income earners, perhaps also with higher educational attainments. Locations close to these places could be relevant for specific firms in order to get access to an attractive pool of labour. This type of reasoning is based on the hypothesis that “jobs follow people”, which subsequently may improve labour market accessibility in places with higher housing prices. Hoogstra et al. (2017) provide a useful meta-analysis of the related literature regarding this question. Their main finding is that the evidence is inconclusive. The causality between jobs and people could run in different directions (pages 371-372). If this holds true, for our data, the resulting bias could be minor, and unpredictable. If there exists reverse causality, identification of the impact of accessibility would necessitate an instrument. One possible instrument could be an exogenous change in measures of accessibility. However, we do not have access to any such instrument. Moreover, we focus on several variables, which are potentially endogenous. Testing for exogeneity is, hence, not straightforward according to e.g. Baum et al. (2007). We have to use several instruments, and in these cases, the traditional IV-estimators could be biased and inconsistent (see also Nordvik et al. 2019, for further discussions of this issue). Finally, it is also possible to argue that the need for an instrument is less important in our case, given the results from the spatial Durbin model. This model accounts for indirect spill over impacts and the spatial Durbin model, in general, is robust to omitted systematic spatial variation of characteristics (LeSage, Pace 2009). 8 Conclusions In explaining spatial variation in housing prices, gravity-based accessibility measures have been suggested as a generalization of modern polycentric labour market structures. From a computational and data collection perspective, it would be convenient if easily available information on actual commuting patterns could replace a more complex measure of commuting potential. According to our results, two of the hypotheses formulated in Section 3 have to be rejected, however. The labour market accessibility effect is not adequately represented by the proposed characteristics of observed commuting patterns. We used a wide range of different methods to obtain robust conclusions. Labour market accessibility in relation to housing prices is best captured by the gravity based potential variable. Our results, on the other hand, provide support for the hypotheses HB 0 and HD 0 . Observed measures of commuting patterns are found to contribute with information that adds to the effect of a potential measure in explaining spatial variation in housing prices. In particular, the results from the ordinary least squares and the spatial Durbin estimator support the hypothesis that a relatively high level of commuting into a zone corresponds to negative externalities, such as noise, pollution, or other negative effects of heavy traffic and/or industrial activities. There is only weak support for the hypothesis that a relatively high level of out-commuting from a zone corresponds to attractive neighbourhood characteristics, which are positively related to housing prices. Average commuting time, a priori, reflect something about the actual commuting costs for households. However, our interpretation of the positive impact of this variable is that a high level of spatial interaction in the central parts of the urban area seem to dominate. Over time, the job growth in the Stavanger urban area has come in areas that used to be the outskirt of the city. Still, some of the residential areas close to the city centre have very high REGION : Volume 7, Number 1, 2020 ===== PAGE 22 (score 101, numeric-paren 75, table-words 1, var-words 4) ===== 70 A. Gjestland, L. Osland, I. Thorsen A Appendix: Results of spatial error model estimations Table A.1: Estimated results for the hedonic house price models based on the spatial error model formulation as specified in equation (9) Variable Name M0 M1 M2 M3 M4 M5 Constant 13.060 12.506 13.031 12.180 12.710 11.596 (120.88) (75.10) (119.33) (66.87) (48.96) (37.09) Lotsize -0.187 -0.204 -0.183 -0.202 -0.189 -0.214 (-6.11) (-6.61) (-5.94)) (-6.56) (-6.15) (-6.93) LotSize2 0.024 0.026 0.024 0.026 0.024 0.026 (9.55) (9.98) (9.39) (9.99) (9.58) (10.30) RurLotsize -0.025 -0.021 -0.026 -0.023 -0.025 -0.019 (-8.76) (-7.26) (-8.86) (-7.86) (-8.73) (6.47) Age -0.1809 -0.178 -0.183 -0.182 -0.182 -0.180 (-10.71) (-10.51) (-10.78) (-10.82) (-10.78) (-10.67) Age2 0.013 0.012 0.013 0.013 0.013 0.013 (4.64) (4.43) (4.75) (4.77) (4.75) (4.60) Garage 0.039 0.040 0.038 0.039 0.039 0.039 (6.71) (6.82) (6.59) (6.70) ( 6.68) (6.67) Size of house 0.493 0.491 0.493 0.490 0.493 0.491 (52.31) (52.19) (52.31) (52.27) (52.47) (52.36) YearDum04 0.0955 0.096 0.096 0.096 0.096 0.096 (9.87) (9.91) (9.87) (9.93) (9.88) (9.90) YearDum05 0.199 0.199 0.199 0.199 0.199 0.199 (20.41) (20.45) (20.39) (20.46) (20.41) (20.43) YearDum06 0.370 0.370 0.370 0.370 0.370 0.370 (38.33) (38.34) (38.34) (38.36) (38.32) (38.35) YearDum07 0.5573 0.557 0.557 0.557 0.557 0.556 (58.91) (58.88) (58.92) (58.93) (58.93) (58.82) DistCBD -0.0574 -0.101 -0.040 -0.105 -0.074 -0.163 (-2.58) (-4.14) (-1.58) (-3.93) (-2.96) (-5.71) DistCBD2 -0.047 -0.029 -0.053 -0.028 -0.045 -0.018 (-11.06) (-5.07) (-9.17) (-3.96) (-9.48) (-2.82) ACCESS 0.059 0.088 0.109 (4.36) (5.81) (6.07) IN-COM -0.033 -0.082 (-1.78) (-4.39) OUT-COM -0.006 0.034 (-0.22) (1.65) MCT 0.315 0.306 (1.48) (1.47) MCT2 -0.063 -0.035 (-1.44) (-0.80) λ 0.374 0.364 0.373 0.359 0.374 0.358 (23.67) (22.85) (23.60) (22.30) (23.60) (22.24) Log-likelihood 1420.26 1429.58 1422.56 1440.23 1422.69 1440.57 Note: Z-values in parentheses. c⃝2020 by the authors. Licensee: REGION – The Journal of ERSA, European Regional Science Association, Louvain-la-Neuve, Belgium. This article is distri- buted under the terms and conditions of the Creative Commons Attribution, Non-Commercial (CC BY NC) license (http://creativecommons.org/licenses/by-nc/4.0/). REGION : Volume 7, Number 1, 2020