农户林地转出规模的门限效应——基于集体林权制度改革监测数据的实证检验

doi:10.11707/j.1001-7488.20200315

摘要/Abstract

摘要：

目的: 揭示农户林地转出行为的门限效应，识别门限特征及其不同门限区域内关键影响因素的非线性作用，为完善林地流转政策提供决策参考。方法: 基于国家林业局2016年集体林权制度改革监测数据及2017年广东和贵州的农户调查数据，分地块构建农户转出林地规模的面板数据，从权能匹配视角选择农户营林规模为门限变量，以家庭收入水平、务农劳动力规模和是否具有林权证为解释变量，运用门限回归模型，实证检验农户林地转出规模的门限效应与各影响因素的非线性作用。结果: 1)当以家庭收入水平和以务农劳动力规模为解释变量时，门限估计显示农户营林规模均存在双重门限，其值分别为18 hm²和20 hm²;当以是否具有林权证为解释变量时，农户营林规模仅有单一门限，其值为33.4 hm²。2)当农户营林规模大于18 hm²时，家庭收入水平对林地转出规模具有显著正向影响，且当营林规模大于20 hm²时，其影响系数明显更大;当农户营林规模小于18 hm²时，务农劳动力规模对林地转出规模具有显著负向影响，而当营林规模大于18 hm²且小于20 hm²时其又具有显著正向影响;当农户营林规模分别小于和大于33.4 hm²时，是否具有林权证对林地转出规模分别具有负向和正向影响，但不显著。根据农户营林规模的门限值对样本进行分组后再回归，以检验估计结果的稳健性，发现各解释变量的影响显著程度与门限估计结果有差异，但方向一致。结论: 农户林地转出行为并不是单向或线性的，关键因素的作用是非线性的。只在一定营林规模水平下，家庭收入的提高才明显促进农户转出林地规模，表明降低农户的林地依赖度未必能促进林地流转。在不同营林规模门限区域内，务农劳动力规模对农户林地转出规模的影响方向不同，即加快农村劳动力转移也未必就能促进林地流转。林地确权对农户林地转出规模的影响也是双向的且均不显著，即林地产权稳定对促进林地流转的重要性不如政策预期。完善林地流转政策需要关注农户行为的门限效应，坚持放松约束未必能促进农村林地流转，甚至可能存在相反作用，制度供给可考虑不同条件下林地流转差异化诉求，加大政策执行弹性与优先序，以提高制度绩效，促进林地规模经营。

关键词: 林地流转, 非线性, 门限效应, 规模经营

Abstract:

Objective: The study is intended to reveal the threshold effect of household forestland transfer. It is important to identify the threshold characteristics and the non-linear effects of key factors in different threshold ranges for supporting decision-making for improving forestland transfer policy. Method: Based on the monitoring data of collective forest tenure reform of the State Forestry Administration in 2016 and survey data of farmers in Guangdong and Guizhou provinces in 2017, the panel data on the size of transferred household forestland was constructed for different forest blocks. From the perspective of power matching, the threshold variable is the size of household forestland management, and the core explanatory variable is the level of family income, the number of household labor force and whether they have forest certificate or not. Using threshold regression model, empirical tests of the threshold effect of the size of household forestland transfer and the non-linear influence of various factors were conducted. Result: Firstly, when the household income level and the number of household farming labors are taken as the core explanatory variables, the threshold estimates show that there are double thresholds for the size of household forestland management, with the values of 18 hm² and 20 hm², respectively. When the core explanatory variable is whether or not the forest ownership certificate exists, there exists a single threshold for the size of household forestland management, with a value of 33.4 hm². Secondly, When the size of household forestland management is more than 18 hm², the level of family income has a significant positive impact on the size of forestland transfer. When the size of forestland management is larger than 20 hm², its influence coefficient is obviously larger. When the size of household forestland management is less than 18 hm², the number of household farming labor has a significant negative impact on the size of forestland transfer. However, when the size of forestland management is more than 18 hm² and less than 20 hm², it has a significant positive impact. When the size of household forestland management is less than or greater than 33.4 hm², whether the ownership certificate has a negative and positive impact on the size of transferred forestland, but not significant. Samples were grouped according to the threshold value of household forestland management and then regression analyses were conducted to test the robustness of the estimated results, the significance of the influence of each core explanatory variable is different from that of the threshold estimation, but the direction is the same. Conclusion: Household forestland transfer is not unidirectional or linear, and the role of key factors has a threshold effect. Only at a certain level of forestland management, the increase of household income significantly promotes the size of forestland transfer. It shows that reducing the dependence of farmers on forestland may not be able to promote the transter of forestland. Within the threshold range for different sizes of forestland management, the impact of household farming labor force on the size of household forestland transfer is different. Transfer of rural labor force may not be able to promote the transfer of forestland. The effect of certification of forestland ownership on the size of household forestland transfer is also bidirectional and not significant, implying that the stabilization of forestland property rights is less important than policy expectation in promoting forestland transfer. Improving the policy on forestland transfer needs to pay attention to the threshold effect of household behavior. Relaxation of restrictions may not promote the transfer of rural forestland and may even have the opposite effect. Institutional supply can take into account the different demands of forestland transfer under different conditions. Increasing the flexibility and priority of policy implementation improves the institutional performance and promotes large-scale management of forestland.

Key words: forestland transfer, nonlinear, threshold effect, scale management

中图分类号:

F307.2

张自强,李怡,高岚. 农户林地转出规模的门限效应——基于集体林权制度改革监测数据的实证检验[J]. 林业科学, 2020, 56(3): 144-155.

Ziqiang Zhang,Yi Li,Lan Gao. Threshold Effect of the Size of Household Forestland Transfer——Empirical Test Based on Monitoring Data of Collective Forest Tenure Reform[J]. Scientia Silvae Sinicae, 2020, 56(3): 144-155.

图/表 6

表1

变量赋值与描述性统计"

变量 Variables	简称 Abbreviation	变量说明 Variable description	均值 Mean	标准差 Std. deviation
转出林地面积Transferred forest area/hm²	Outflow area	农户已转出林地面积 Total area of farmer’s transferred forestland	8.628	20.512
营林规模Forestland management area/hm²	Forestland	农户现有林地经营面积 Farmer’s forestland management area	5.625	15.581
务农劳动力规模Scale of farming labor force	Labor	家庭务农劳动力数Number of household labors	2.860	1.371
家庭收入水平Household income level	Income	家庭收入在村里水平的自我评价：较高=3，中等=2，较低=1 Self-evaluation of family income at village level: higher=3, medium=2, lower=1	1.914	0.529
是否有林权证 Whether it has forest ownership certificate	Certificate	是=1，否=0 Yes=1, not=0	0.901	0.3
年龄Age/a	Age	户主年龄Age of head of household	54.432	10.883
受教育程度Level of education	Edu	户主受教育程度：小学及以下=6，初中=9，高中=12，大专或本科及以上=16 Educational level of householders: primary school and below=6, junior high school=9, senior high school=12, junior college or undergraduate or above=16	8.352	2.358
是否为用材林Whether it is timber forest or not	Timber	是=1，否=0 Yes=1, not=0	0.264	0.441
是否为经济林 Whether it is economic forest or not	Economic forest	是=1，否=0 Yes=1, not=0	0.171	0.377
是否为竹林Whether it is bamboo or not	Bamboo	是=1，否=0 Yes=1, not=0	0.075	0.264
近3年是否有森林灾害Whether it has forest disaster in the past three years or not	Disaster	是=1，否=0 Yes=1, not=0	0.014	0.116
林地是否流转给本村村民Whether the woodland is transferred to the villagers or not	Native villager	是=1，否=0 Yes=1, not=0	0.250	0.434
是否有林权抵押贷款Whether participation in forestry mortgage loan or not	Mortgage	是=1，否=0 Yes=1, not=0	0.030	0.171
是否参与森林保险Whether participation in forest insurance or not	Insurance	是=1，否=0 Yes=1, not=0	0.382	0.486
对采伐管制满意度 Satisfaction with logging control	Logging	满意=3，一般=2，不满意=1 Satisfaction=3, general=2, dissatisfaction=1	1.950	1.250

表1

表2

表3

表4

表5

表6

参考文献 0

	蔡银莺, 王亚运, 朱兰兰. 城市边缘区农户耕地利用功能对土地转出的影响——武汉、成都、苏州1 022户农民的典型实证. 自然资源学报, 2016. 31 (10): 1648- 1661. doi: 10.11849/zrzyxb.20151255
	Cai Y Y , Wang Y Y , Zhu L L . The effect of farmer households' farmland use function on their land rental decision in urban fringe:a case study of 1 022 farmer households in Suzhou, Chengdu and Wuhan. Journal of Natural Resources, 2016. 31 (10): 1648- 1661. doi: 10.11849/zrzyxb.20151255
	陈念东, 刘祖军. 集体林权流转弱市场化困境的思考——基于交易费用理论视角. 林业经济问题, 2012. 32 (5): 392- 396. doi: 10.3969/j.issn.1005-9709.2012.05.004
	Chen N D , Liu Z J . The thinking of weak collective forest right circulation trouble based on the transaction cost theory perspective. Issues of Forestry Economics, 2012. 32 (5): 392- 396. doi: 10.3969/j.issn.1005-9709.2012.05.004
	高岚, 徐冬梅. 个体禀赋与认知对农户林地流转行为的影响——基于意愿与行为一致视角分析. 林业科学, 2018. 54 (7): 137- 145.
	Gao L , Xu D M . Influence of individual endowment and cognition on the behavior of farmers in forestland circulation:based on the view of intention-behavior consistency. Scientia Silvae Sinicae, 2018. 54 (7): 137- 145.
	何文剑, 张红霄, 汪海燕. 林权改革、林权结构与农户采伐行为——基于南方集体林区7个重点林业县(市)林改政策及415户农户调查数据. 中国农村经济, 2014. (7): 81- 96.
	He W J , Zhang H X , Wang H Y . Forest right reform, forest right structure and farmers' cutting behavior——based on the forest reform policy of 7 key forestry counties (cities) and 415 farmer households survey data in southern collective forest region. Chinese Rural Economy, 2014. (7): 81- 96.
	黄佩红, 李琴, 李大胜. 新一轮确权能促进农地流转吗?. 经济经纬, 2018. (4): 44- 49.
	Huang P H , Li Q , Li D S . Does the latest rural land right verification promote the transfer of farmland? Economic Survey, (4):44-49. Economic Survey, 2018. (4): 44- 49.
	柯水发, 英犁, 赵铁珍. 集体林区林地使用权流转分析——政策演进、流转形式及机制. 林业经济, 2012. (3): 12- 16. doi: 10.3969/j.issn.1673-5919.2012.03.007
	Ke S F , Ying L , Zhao T Z . Analysis of forestland usufruct transfer in collective forest areas——policy process, types and mechanisms. Forestry Economics, 2012. (3): 12- 16. doi: 10.3969/j.issn.1673-5919.2012.03.007
	冷智花, 付畅俭, 许先普. 家庭收入结构、收入差距与土地流转——基于中国家庭追踪调查(CFPS)数据的微观分析. 经济评论, 2015. (5): 111- 128.
	Leng Z H , Fu C J , Xu X P . Family income structure, income gap, and land circulation:a microscopic analysis based on CFPS data. Economic Review, 2015. (5): 111- 128.
	李博, 李桦. 农户林地未流转行为影响因素分析. 林业经济问题, 2012. 32 (4): 348- 353. doi: 10.3969/j.issn.1005-9709.2012.04.013
	Li B , Li H . Analysis on factors affecting the households' deciding behavior in forest land non-transaction. Issues of Forestry Economics, 2012. 32 (4): 348- 353. doi: 10.3969/j.issn.1005-9709.2012.04.013
	李琴, 李大胜, 李承政. 家庭农地禀赋与农地流转决策——基于非线性关系的考察. 浙江社会科学, 2015. (10): 19- 28.
	Li Q , Li D S , Li C Z . Household land endowment and land transfer decision——based on the non-linear relationship. Zhejiang Social Sciences, 2015. (10): 19- 28.
	李彧挥, 方苑, 陈亮. 林农流转出林地意愿的影响因素分析——以湖南省安化县为例. 江汉论坛, 2012. (2): 14- 19. doi: 10.3969/j.issn.1003-854X.2012.02.002
	Li Y H , Fang Y , Chen L . Analysis on the influencing factors of forest farmers' willingness to transfer out of forest land——a case study of Anhua county, Hunan province. Jianghan Tribune, 2012. (2): 14- 19. doi: 10.3969/j.issn.1003-854X.2012.02.002
	林丽梅, 刘振滨, 许佳贤. 家庭禀赋对农户林地流转意愿及行为的影响——基于闽西北集体林区农户调查. 湖南农业大学学报:社会科学版, 2016. 17 (2): 16- 21.
	Lin L M , Liu Z B , Xu J X . Influence of family endowment on farmers' intention and behavior of forest land circulation:based on the investigation of households in collective forest area of northwest Fujian Province. Journal of Hunan Agricultural University:Social Sciences, 2016. 17 (2): 16- 21.
	吕杰, 冉陆荣. 林地流转中不同类型农户决策行为博弈分析. 中国土地科学, 2011. 25 (4): 31- 35.
	Lü J , Ran L R . Game analysis on decision-making behaviors of various types of farmers during forestland transfer. China Land Science, 2011. 25 (4): 31- 35.
	罗必良. 农地保障和退出条件下的制度变革:福利功能让渡财产功能. 改革, 2013. (1): 66- 75.
	Luo B L . The institutional change under the circumstance of farmland security and exit conditions:welfare function to property function. Reform, 2013. (1): 66- 75.
	罗必良. 农地流转的市场逻辑——"产权强度-禀赋效应-交易装置"的分析线索及案例研究. 南方经济, 2014. 32 (5): 1- 24. doi: 10.3969/j.issn.1000-6249.2014.05.001
	Luo B L . Market logic of farmland circulation:"strength of property rights-endowment effect-transaction configuration" as a clue and case study. South China Journal of Economics, 2014. 32 (5): 1- 24. doi: 10.3969/j.issn.1000-6249.2014.05.001
	普蓂喆, 郑风田. 初始禀赋、土地依赖与农户土地转出行为分析——基于23省5 165个农户样本的实证分析. 华中科技大学学报:社会科学版, 2016. 30 (1): 42- 50.
	Pu M Z , Zheng F T . Initial endowment, land reliance and land outward transfer in rural China——evidence from 5 165 rural households in 23 provinces. Journal of Huazhong University of Science and Technology:Social Science Edition, 2016. 30 (1): 42- 50.
	史若昀, 刘伟平. 基于产权强度理论的林地流转行为研究——以福建省10县(市)50村农户调查为例. 东南学术, 2017. (4): 86- 93.
	Shi R Y , Liu W P . Study on forest land transfer behavior based on the intensity of property rights theory:data from 50 towns in 10 counties and cities in Fujian province. Southeast Academic Research, 2017. (4): 86- 93.
	王波, 吕士福, 黄和亮, 等. 农户林地流转行为的关键影响因素研究. 林业经济, 2017. (4): 59- 62, 67.
	Wang B , Lü S F , Huang H L , et al. Study on the key factors of farmers' forestland circulation behavior. Forestry Economics, 2017. (4): 59- 62, 67.
	王成军, 费喜敏, 徐秀英. 农村劳动力转移与农户间林地流转——基于浙江省两个县(市)调查的研究. 自然资源学报, 2012. 27 (6): 893- 900.
	Wang C J , Fei X M , Xu X Y . Rural labor transfer and woodland circulation between rural households——research statistics on two counties of Zhejiang province. Journal of Natural Resources, 2012. 27 (6): 893- 900.
	肖慧婷, 谢芳婷, 杜娟, 等. 农户资源禀赋差异性对林地流转行为影响实证研究——基于江西集体林区10县503农户的调查. 林业经济, 2018. (11): 44- 51.
	Xiao H T , Xie F T , Du J , et al. An empirical research on the impact of the difference in householder resource endowments on forestland circulation behavior——survey of 503 householders from 10 counties in collective forest regions in Jiangxi province. Forestry Economics, 2018. (11): 44- 51.
	谢煜, 朱小静, 温作民, 等. 为什么小规模林农没有选择场内交易——来自浙江的实证研究. 农林经济管理学报, 2016. 15 (3): 271- 279.
	Xie Y , Zhu X J , Wen Z M , et al. Why small-scale forest farmers do not choose public forest tenure trade market:an empirical research of Zhejiang province. Journal of Agro-Forestry Economics and Management, 2016. 15 (3): 271- 279.
	徐堇寒, 徐秀英. 农户生计非农化对林地转出意愿的影响研究. 林业经济问题, 2018. 38 (2): 17- 22, 103.
	Xu J H , Xu X Y . Impact of rural households' non-agricultural employment on willingness of forestland outflow. Issues of Forestry Economics, 2018. 38 (2): 17- 22, 103.
	徐秀英, 石道金, 杨松坤, 等. 农户林地流转行为及影响因素分析——基于浙江省临安、安吉的农户调查. 林业科学, 2010. 46 (9): 149- 157.
	Xu X Y , Shi D J , Yang S K , et al. Analysis on forestland transferring and the affecting factors:a case study in Lin'an and Anji county in Zhejiang province. Scientia Silvae Sinicae, 2010. 46 (9): 149- 157.
	许凯, 张升. 集体林地流转影响因素分析——基于7省3 500个样本农户数据. 林业经济, 2015. (4): 12- 20. doi: 10.3969/j.issn.1672-7789.2015.04.004
	Xu K , Zhang S . Analysis on factors influencing forestland transfer——a study based on survey data of 3 500 households in 7 provinces in China. Forestry Economics, 2015. (4): 12- 20. doi: 10.3969/j.issn.1672-7789.2015.04.004
	乐章. 农民土地流转意愿及解释——基于十省份千户农民调查数据的实证分析. 农业经济问题, 2010. 31 (2): 64- 70.
	Yue Z . The willingness of farmers' land transaction and explanation:an empirical analysis based on survey data from 1 032 farmers in ten provinces and cities. Issues in Agricultural Economy, 2010. 31 (2): 64- 70.
	张寒, 杨红强, 陈海滨, 等. 非农就业对林地流转的影响——基于双内生视角的MV Tobit估计. 资源科学, 2018. 40 (8): 1505- 1514.
	Zhang H , Yang H Q , Chen H B , et al. The effects of off-farm employment on forestland transfer:the MV Tobit estimation with endogeneity perspectives. Resources Science, 2018. 40 (8): 1505- 1514.
	张舟, 谭荣, 石琛, 等. 林地流转模式的选择机理及其政策启示. 中国土地科学, 2014. 28 (5): 11- 18. doi: 10.3969/j.issn.1001-8158.2014.05.002
	Zhang Z , Tan R , Shi C , et al. The selection mechanism of forestland transfer modes and its policy implications. China Land Science, 2014. 28 (5): 11- 18. doi: 10.3969/j.issn.1001-8158.2014.05.002
	朱文清, 张莉琴. 集体林地确权到户对林地流转的政策效果分析. 资源科学, 2018. 40 (7): 1407- 1417.
	Zhu W Q , Zhang L Q . The impact of confirming collective forest land property rights to households on the forest land circulation behavior of farmers. Resources Science, 2018. 40 (7): 1407- 1417.
	Deininger K , Jin S . The potential of land rental markets in the process of economic development:Evidence from China. Journal of Development Economics, 2005. 78 (1): 241- 270. doi: 10.1016/j.jdeveco.2004.08.002
	Dijk T V . Scenarios of central European land fragmentation. Land Use Policy, 2003. 20 (2): 149- 158. doi: 10.1016/S0264-8377(02)00082-0
	Granovetter M . Threshold models of collective behavior. American Journal of Sociology, 1978. 83 (6): 1420- 1443. doi: 10.1086/226707
	Hansen B E . Sample splitting and threshold estimation. Econometrica, 2000. 68 (3): 575- 603. doi: 10.1111/1468-0262.00124
	Heller M . The tragedy of the anticommons:a concise introduction and lexicon. The Modern Law Review, 2013. 76 (1): 6- 25. doi: 10.1111/1468-2230.12000
	Ilbery B W . Farm fragmentation in the Vale of Evesham. Area, 1984. 16 (2): 159- 165.
	Kahneman D , Tversky K A . Prospect theory:an analysis of decision under risk. Econometrica, 1979. 47 (2): 263- 292. doi: 10.2307/1914185
	Schmidt T L , Raile G K . Forest fragmentation in the Lake States. Proceedings of the Society of American Foresters National Convention, 1999. (1): 107- 115.
	Wang Q Y . Fixed-effect panel threshold model using Stata. The Stata Journal, 2015. 15 (1): 121- 134.

变量Variables	频数Frequency	频率Rate(%)
营林规模Forestland management area/hm²
< 2	87	37.8
[2, 7]	76	33.0
(7, 14]	22	9.6
>14	45	19.6
转出林地面积Transferred forest area/hm²
< 2	63	27.4
[2, 7]	83	36.1
(7, 14]	34	14.8
>14	50	21.7
转出地块数Number of transferred plots
< 2	103	44.9
[2, 4]	115	49.7
>4	12	5.4

解释变量 Explanatory variables	门限个数 Threshold number	F	P	Crit10	Crit5	Crit1
Income	双重门限Double threshold	26.99^***	0.000	12.717	15.199	19.337
Income	三重门限Triple threshold	5.94	0.470	62.857	95.217	140.190
Labor	双重门限Double threshold	15.19^**	0.020	9.440	10.285	22.536
Labor	三重门限Triple threshold	7.15	0.100	5.650	17.730	17.729
Certificate	单一门限Single threshold	10.15	0.095	9.856	12.675	15.926
Certificate	双重门限Double threshold	3.40	0.600	7.658	7.658	7.658

解释变量Explanatory variables	门限估计值 Estimate of threshold value	置信区间(95%) Confidence interval(95%)
Income	γ₁=18	[16, 20]
Income	γ₂=20	[18, 21]
Labor	γ₁=18	[16, 20]
Labor	γ₂=20	[18, 21]
Certificate	γ₁=33.4	[32, 37]

变量Variables	系数1 Coefficient 1	标准误1 Standard error 1	系数2 Coefficient 2	标准误2 Standard error 2	系数3 Coefficient 3	标准误3 Standard error 3
Age	-0.063	0.048	-0.104^*	0.059	-0.118^*	0.060
Edu	0.079	0.213	0.142	0.260	0.132	0.263
Labor	-0.846^**	0.395			-0.666	0.497
Income			1.702^*	1.002	1.918^*	1.019
Timber	0.585	1.818	0.407	2.229	-0.116	2.336
Economic forest	2.054	1.783	1.329	2.185	0.143	2.299
Bamboo	-0.853	2.464	0.806	2.994	1.302	3.132
Certificate	0.671	1.576	-0.408	1.938
Disaster	-1.614	3.252	-1.196	3.994	-1.165	4.102
Native villager	-0.380	1.245	-0.862	1.512	-1.541	1.562
Mortgage	-76.212^***	7.601	-50.145^***	8.917	-36.974	8.598
Insurance	0.792	1.620	1.254	1.974	1.766^***	2.018
Logging	0.180	0.488	-0.498	0.583	-0.625	0.599
Constant	3.246	4.537	6.853	5.494	8.540	5.636
Income(forestland < 18 hm²)	0.874	0.834
Income(18 hm²≤forestland < 20 hm²)	4.157^**	1.890
Income(20 hm²≤forestland)	28.491^***	2.526
Labor (forestland < 18 hm²)			-0.943^*	0.485
Labor (18 hm² ≤forestland < 20 hm²)			4.022^***	1.336
Labor (20 hm²≤forestland)			-0.019	0.816
Certificate(forestland < 33.4 hm²)					-1.683	1.982
Certificate(33.4 hm²≤forestland)					4.015	4.040
sigma_u	61.532		75.984		78.711
sigma_e	82.454		101.17		104.216
rho	0.358		0.361		0.363
F	1.62^***		1.48^**		1.51^**

变量 Variables	Forestland < 18 hm² 固定效应 Fixed effect	18 hm²≤Forestland < 20 hm² 固定效应 Fixed effect	Forestland≥20 hm² 随机效应 Random effects	Forestland < 33.4 hm² 固定效应 Fixed effect	Forestland≥33.4 hm² 随机效应 Random effects
Labor	-0.013 (2.639)	0.055^* (5.322)	-5.472 (67.813)
Income	0.287^* (5.398)	0.374^* (7.540)	3.184 (65.882)
Certificate				-1.102 (30.094)	1.654 (21.641)
Control variables	yes	yes	yes	yes	yes
Constant	-0.575 (29.422)	0.504 (57.451)	60.709 (771.711)	6.584 (85.961)	13.466 (231.437)
sigma_u	32.178	24.752	52.099	79.528	133.563
sigma_e	33.976	51.364	68.376	104.671	39.993
rho	0.473	0.511 6	0.367	0.366	0.918
F	1.78^*	1.64^*		2.57^***
Wald			17.64^*		76.09^***