[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.40,0:00:03.05,Default,,0000,0000,0000,,从原因到结果的路径
Dialogue: 0,0:00:03.05,0:00:05.54,Default,,0000,0000,0000,,既黑暗且危险的
Dialogue: 0,0:00:05.54,0:00:08.90,Default,,0000,0000,0000,,但是计量经济学的武器非常强大
Dialogue: 0,0:00:09.21,0:00:13.70,Default,,0000,0000,0000,,当目睹平行趋势时\N我们掌握了双重差分法
Dialogue: 0,0:00:14.45,0:00:16.85,Default,,0000,0000,0000,,♪ [] ♪
Dialogue: 0,0:00:20.10,0:00:21.42,Default,,0000,0000,0000,,计量经济学大师在寻找
Dialogue: 0,0:00:21.42,0:00:24.80,Default,,0000,0000,0000,,令人信服的\N「其他条件不变的比较」
Dialogue: 0,0:00:25.10,0:00:29.42,Default,,0000,0000,0000,,理想的对比是
Dialogue: 0,0:00:29.42,0:00:30.60,Default,,0000,0000,0000,,看起来相似的处理组和对照组\N形成对照
Dialogue: 0,0:00:30.60,0:00:34.63,Default,,0000,0000,0000,,但有时这种可比性是难以捉摸的
Dialogue: 0,0:00:34.63,0:00:36.80,Default,,0000,0000,0000,,在没有处理的情况下
Dialogue: 0,0:00:36.80,0:00:40.10,Default,,0000,0000,0000,,当处理组及对照组类似地演变时
Dialogue: 0,0:00:40.10,0:00:42.31,Default,,0000,0000,0000,,即使起点不同
Dialogue: 0,0:00:42.31,0:00:44.90,Default,,0000,0000,0000,,也有望进行因果推断
Dialogue: 0,0:00:45.60,0:00:48.40,Default,,0000,0000,0000,,针对平行演化的武器
Dialogue: 0,0:00:48.66,0:00:50.89,Default,,0000,0000,0000,,大师说的「平行趋势」
Dialogue: 0,0:00:50.89,0:00:53.23,Default,,0000,0000,0000,,叫做「双重差分法」…
Dialogue: 0,0:00:53.23,0:00:54.42,Default,,0000,0000,0000,,- 双重差分法...
Dialogue: 0,0:00:54.42,0:00:56.90,Default,,0000,0000,0000,,- ...或简称为DD\N- 好的
Dialogue: 0,0:00:56.90,0:00:59.99,Default,,0000,0000,0000,,- 现在让我们看看 DD
Dialogue: 0,0:00:59.99,0:01:02.89,Default,,0000,0000,0000,,如何帮助我们了解美国历史上
Dialogue: 0,0:01:02.89,0:01:04.37,Default,,0000,0000,0000,,最重要的经济事件之一
Dialogue: 0,0:01:05.30,0:01:08.30,Default,,0000,0000,0000,,- 现在我们一起回顾大萧条的情況—
Dialogue: 0,0:01:08.80,0:01:12.20,Default,,0000,0000,0000,,我国有史以来最严重的经济灾难
Dialogue: 0,0:01:13.10,0:01:16.20,Default,,0000,0000,0000,,在 1933 年失业率达到 25%—
Dialogue: 0,0:01:16.60,0:01:19.11,Default,,0000,0000,0000,,这是之前或之后从未见过的水平
Dialogue: 0,0:01:19.47,0:01:22.10,Default,,0000,0000,0000,,数百万国民失去了家园或土地
Dialogue: 0,0:01:22.60,0:01:24.74,Default,,0000,0000,0000,,自杀率飙升
Dialogue: 0,0:01:24.74,0:01:26.77,Default,,0000,0000,0000,,贫困的家庭依靠施食处和面包生产线
Dialogue: 0,0:01:26.77,0:01:28.16,Default,,0000,0000,0000,,来避免挨饿
Dialogue: 0,0:01:29.40,0:01:31.59,Default,,0000,0000,0000,,- 经济学家们
Dialogue: 0,0:01:31.59,0:01:34.00,Default,,0000,0000,0000,,就大萧条的原因展开了激烈的争论
Dialogue: 0,0:01:34.00,0:01:36.98,Default,,0000,0000,0000,,然而，大多数经济学家都同意\N这个难题的关键部分
Dialogue: 0,0:01:36.98,0:01:39.46,Default,,0000,0000,0000,,是银行大规模倒闭
Dialogue: 0,0:01:39.80,0:01:41.90,Default,,0000,0000,0000,,这是施行存款保险制度之前的年代
Dialogue: 0,0:01:42.10,0:01:46.51,Default,,0000,0000,0000,,因此，如果银行破产\N你的储蓄也会化为乌有
Dialogue: 0,0:01:46.51,0:01:47.67,Default,,0000,0000,0000,,- 取消你的帐户？
Dialogue: 0,0:01:47.67,0:01:48.89,Default,,0000,0000,0000,,- 对啊，我想取消我的帐户
Dialogue: 0,0:01:48.89,0:01:50.62,Default,,0000,0000,0000,,我不会在这家银行留下一分钱
Dialogue: 0,0:01:52.60,0:01:56.10,Default,,0000,0000,0000,,- 面对银行业危机，央行有一项选择
Dialogue: 0,0:01:56.40,0:01:58.52,Default,,0000,0000,0000,,随意地放贷给陷入困境的银行
Dialogue: 0,0:01:58.52,0:02:01.10,Default,,0000,0000,0000,,或者袖手旁观拒绝贷款
Dialogue: 0,0:02:01.50,0:02:05.44,Default,,0000,0000,0000,,借钱给有困难的银行叫「易钱」
Dialogue: 0,0:02:05.44,0:02:08.10,Default,,0000,0000,0000,,拒贷叫「紧钱」
Dialogue: 0,0:02:10.20,0:02:12.87,Default,,0000,0000,0000,,- 货币学派的代表人物\N米尔顿弗里德曼和安娜施瓦茨
Dialogue: 0,0:02:12.87,0:02:14.88,Default,,0000,0000,0000,,把大萧条称为
Dialogue: 0,0:02:14.88,0:02:16.35,Default,,0000,0000,0000,,「大收缩」
Dialogue: 0,0:02:16.80,0:02:18.26,Default,,0000,0000,0000,,指责美联储
Dialogue: 0,0:02:18.26,0:02:21.20,Default,,0000,0000,0000,,就国家摇摇欲坠的金融机构\N实施紧缩政策
Dialogue: 0,0:02:21.20,0:02:24.00,Default,,0000,0000,0000,,是一项错误的政策
Dialogue: 0,0:02:24.36,0:02:25.74,Default,,0000,0000,0000,,他们争辩说
Dialogue: 0,0:02:25.74,0:02:27.90,Default,,0000,0000,0000,,易钱可让许多银行继续营业
Dialogue: 0,0:02:27.90,0:02:29.70,Default,,0000,0000,0000,,从而缩短大萧条的时期
Dialogue: 0,0:02:30.40,0:02:32.11,Default,,0000,0000,0000,,但其他人不同意
Dialogue: 0,0:02:32.11,0:02:33.77,Default,,0000,0000,0000,,如果银行因为其不明智的贷款决定
Dialogue: 0,0:02:33.77,0:02:35.95,Default,,0000,0000,0000,,而资不抵债
Dialogue: 0,0:02:35.95,0:02:38.90,Default,,0000,0000,0000,,那么救助只会鼓励更多的愚蠢行为
Dialogue: 0,0:02:39.60,0:02:42.96,Default,,0000,0000,0000,,经济学家把这个问题称为「道德风险」
Dialogue: 0,0:02:42.96,0:02:46.10,Default,,0000,0000,0000,,今天人们仍就救助和道德风险\N继续进行辩论
Dialogue: 0,0:02:46.50,0:02:48.60,Default,,0000,0000,0000,,如果金融巨头雷曼兄弟
Dialogue: 0,0:02:48.60,0:02:51.50,Default,,0000,0000,0000,,被允许在大衰退前夕倒闭
Dialogue: 0,0:02:52.00,0:02:54.70,Default,,0000,0000,0000,,在理想的世界里\N我们将会通过对随机选择的地区
Dialogue: 0,0:02:54.70,0:02:58.40,Default,,0000,0000,0000,,应用不同的美联储政策\N来回答这个问题
Dialogue: 0,0:02:59.00,0:03:00.25,Default,,0000,0000,0000,,但是通过使用双重差分法
Dialogue: 0,0:03:00.25,0:03:02.12,Default,,0000,0000,0000,,来比较不同货币政策的跨领域趋势
Dialogue: 0,0:03:02.12,0:03:06.30,Default,,0000,0000,0000,,我们仍然可以学到很多事情
Dialogue: 0,0:03:10.81,0:03:12.52,Default,,0000,0000,0000,,- 这怎么可能呢？
Dialogue: 0,0:03:12.52,0:03:15.62,Default,,0000,0000,0000,,所有美国银行不是实施\N相同的美联储政策吗？
Dialogue: 0,0:03:15.62,0:03:17.40,Default,,0000,0000,0000,,- 对啊\N- 好问题
Dialogue: 0,0:03:17.70,0:03:21.48,Default,,0000,0000,0000,,联邦储备系统分为 12 个区
Dialogue: 0,0:03:21.48,0:03:23.86,Default,,0000,0000,0000,,由12家地区性的联邦储备银行组成
Dialogue: 0,0:03:24.30,0:03:27.47,Default,,0000,0000,0000,,今天，美联储政策是在国家层面制定的
Dialogue: 0,0:03:27.47,0:03:31.97,Default,,0000,0000,0000,,但在 1930 年代，地区性的\N联邦储备银行几乎可以随心所欲
Dialogue: 0,0:03:31.97,0:03:33.28,Default,,0000,0000,0000,,- 啊，真有趣
Dialogue: 0,0:03:33.28,0:03:35.50,Default,,0000,0000,0000,,- 这就是最棒的地方
Dialogue: 0,0:03:35.50,0:03:39.30,Default,,0000,0000,0000,,在1930 年代，管理第六区的\N亚特兰大联邦储备银行
Dialogue: 0,0:03:39.30,0:03:41.47,Default,,0000,0000,0000,,遵循「易钱」政策
Dialogue: 0,0:03:41.47,0:03:45.40,Default,,0000,0000,0000,,用手推车运送现金\N去拯救破产的金融机构
Dialogue: 0,0:03:45.90,0:03:48.82,Default,,0000,0000,0000,,而管理第八区的\N圣路易斯联邦储备银行
Dialogue: 0,0:03:48.82,0:03:50.67,Default,,0000,0000,0000,,则采取了紧缩的资金政策
Dialogue: 0,0:03:51.10,0:03:53.90,Default,,0000,0000,0000,,「让愚蠢的人倒下吧！」\N他们在圣路易斯说
Dialogue: 0,0:03:54.30,0:03:58.22,Default,,0000,0000,0000,,因此，货币政策的自然实验诞生了
Dialogue: 0,0:03:58.70,0:04:02.00,Default,,0000,0000,0000,,更好的是，这是州内的实验
Dialogue: 0,0:04:02.00,0:04:04.35,Default,,0000,0000,0000,,第 6 区和第 8 区之间的边界
Dialogue: 0,0:04:04.35,0:04:06.76,Default,,0000,0000,0000,,穿过密西西比州中部
Dialogue: 0,0:04:07.30,0:04:09.32,Default,,0000,0000,0000,,密西西比北部实施紧钱政策
Dialogue: 0,0:04:09.32,0:04:11.87,Default,,0000,0000,0000,,而密西西比南部则实施易钱政策
Dialogue: 0,0:04:11.87,0:04:15.20,Default,,0000,0000,0000,,但是两个地区施行相同的\N州法律和银行法规
Dialogue: 0,0:04:15.52,0:04:16.85,Default,,0000,0000,0000,,- 密西西比州第 6 区
Dialogue: 0,0:04:16.85,0:04:19.98,Default,,0000,0000,0000,,是处理组
Dialogue: 0,0:04:19.98,0:04:23.10,Default,,0000,0000,0000,,在金融危机期间可以获得「易钱」
Dialogue: 0,0:04:23.80,0:04:25.09,Default,,0000,0000,0000,,密西西比州第 8 区
Dialogue: 0,0:04:25.09,0:04:27.80,Default,,0000,0000,0000,,是对照组
Dialogue: 0,0:04:27.80,0:04:30.22,Default,,0000,0000,0000,,在金融危机期间实施「紧钱」政策
Dialogue: 0,0:04:31.30,0:04:34.04,Default,,0000,0000,0000,,1930 年是
Dialogue: 0,0:04:34.04,0:04:35.40,Default,,0000,0000,0000,,自然实验的关键年份
Dialogue: 0,0:04:35.80,0:04:37.44,Default,,0000,0000,0000,,考德威尔公司
Dialogue: 0,0:04:37.44,0:04:40.38,Default,,0000,0000,0000,,是一个位于南方的庞大金融帝国
Dialogue: 0,0:04:40.38,0:04:41.99,Default,,0000,0000,0000,,垮台了
Dialogue: 0,0:04:42.70,0:04:46.00,Default,,0000,0000,0000,,银行业建立在信心和信任的基础上
Dialogue: 0,0:04:46.50,0:04:49.15,Default,,0000,0000,0000,,考德威尔的垮台引发了恐慌
Dialogue: 0,0:04:49.15,0:04:53.05,Default,,0000,0000,0000,,一下子导致了大规模的银行挤兑
Dialogue: 0,0:04:53.05,0:04:55.11,Default,,0000,0000,0000,,存款人想拿回他们的钱
Dialogue: 0,0:04:55.11,0:04:58.20,Default,,0000,0000,0000,,导致银行破产并关门大吉
Dialogue: 0,0:05:01.00,0:05:03.32,Default,,0000,0000,0000,,我们将会使用双重差分法
Dialogue: 0,0:05:03.32,0:05:06.61,Default,,0000,0000,0000,,来衡量相反的货币政策的影响
Dialogue: 0,0:05:06.61,0:05:09.16,Default,,0000,0000,0000,,以应对考德威尔危机
Dialogue: 0,0:05:12.50,0:05:16.28,Default,,0000,0000,0000,,这幅图按年份绘制了
Dialogue: 0,0:05:16.28,0:05:18.76,Default,,0000,0000,0000,,密西西比州第8区和第6区的\N银行数目
Dialogue: 0,0:05:19.27,0:05:21.41,Default,,0000,0000,0000,,我们从 1929 年开始
Dialogue: 0,0:05:21.41,0:05:24.20,Default,,0000,0000,0000,,这是考德威尔垮台前一年
Dialogue: 0,0:05:24.20,0:05:27.56,Default,,0000,0000,0000,,在8区有169家银行开业
Dialogue: 0,0:05:27.56,0:05:31.24,Default,,0000,0000,0000,,而在6区有141家银行开业
Dialogue: 0,0:05:31.24,0:05:32.57,Default,,0000,0000,0000,,在接下来的一年里
Dialogue: 0,0:05:32.57,0:05:37.00,Default,,0000,0000,0000,,我们在两个地区都看到\N类似的少数银行倒闭
Dialogue: 0,0:05:37.40,0:05:40.14,Default,,0000,0000,0000,,运营银行数目的变化
Dialogue: 0,0:05:40.14,0:05:42.17,Default,,0000,0000,0000,,非常相似—
Dialogue: 0,0:05:42.17,0:05:44.60,Default,,0000,0000,0000,,这就是平行趋势的样子
Dialogue: 0,0:05:45.50,0:05:48.78,Default,,0000,0000,0000,,于1930 年 11 月，考德威尔倒下
Dialogue: 0,0:05:48.78,0:05:50.40,Default,,0000,0000,0000,,恐慌开始了
Dialogue: 0,0:05:51.20,0:05:53.92,Default,,0000,0000,0000,,施行紧钱政策的 8 区银行
Dialogue: 0,0:05:53.92,0:05:55.30,Default,,0000,0000,0000,,倒闭频发
Dialogue: 0,0:05:55.80,0:05:58.71,Default,,0000,0000,0000,,但是施行易钱政策的6区银行
Dialogue: 0,0:05:58.71,0:06:00.25,Default,,0000,0000,0000,,倒闭速度较慢
Dialogue: 0,0:06:00.80,0:06:03.00,Default,,0000,0000,0000,,这一时期的分化趋势
Dialogue: 0,0:06:03.00,0:06:06.60,Default,,0000,0000,0000,,可能归因于易钱与紧钱的分别
Dialogue: 0,0:06:06.60,0:06:12.02,Default,,0000,0000,0000,,在1931年7月，8区放弃紧钱政策
Dialogue: 0,0:06:12.02,0:06:14.42,Default,,0000,0000,0000,,在两个区都施行易钱政策
Dialogue: 0,0:06:14.70,0:06:16.90,Default,,0000,0000,0000,,平行趋势得以恢复
Dialogue: 0,0:06:17.30,0:06:19.23,Default,,0000,0000,0000,,在反事实的世界里
Dialogue: 0,0:06:19.23,0:06:22.42,Default,,0000,0000,0000,,6 区银行亦施行紧钱政策的话
Dialogue: 0,0:06:22.42,0:06:23.80,Default,,0000,0000,0000,,那会发生什么事呢？
Dialogue: 0,0:06:24.20,0:06:28.55,Default,,0000,0000,0000,,如果我们将第 8 区的趋势\N推断到第 6 区
Dialogue: 0,0:06:28.55,0:06:29.90,Default,,0000,0000,0000,,看起来就像这样子
Dialogue: 0,0:06:30.29,0:06:33.10,Default,,0000,0000,0000,,因此有效的「易钱」政策
Dialogue: 0,0:06:33.10,0:06:36.46,Default,,0000,0000,0000,,使 6 区偏离 8 区趋势
Dialogue: 0,0:06:36.46,0:06:38.90,Default,,0000,0000,0000,,所默示的路径
Dialogue: 0,0:06:41.24,0:06:44.48,Default,,0000,0000,0000,,「易钱」政策拯救了多少家银行呢？
Dialogue: 0,0:06:44.48,0:06:49.02,Default,,0000,0000,0000,,这个表的第一行报告了
Dialogue: 0,0:06:49.02,0:06:50.16,Default,,0000,0000,0000,,第 6 区处理组的数据
Dialogue: 0,0:06:50.16,0:06:54.24,Default,,0000,0000,0000,,第二行报告了第 8 区对照组的数据
Dialogue: 0,0:06:54.24,0:06:57.49,Default,,0000,0000,0000,,第一列显示了 1930 年危机开始之前
Dialogue: 0,0:06:57.49,0:07:00.61,Default,,0000,0000,0000,,营运银行的数目
Dialogue: 0,0:07:00.61,0:07:03.67,Default,,0000,0000,0000,,第二列显示 1931 年的数目
Dialogue: 0,0:07:03.90,0:07:05.61,Default,,0000,0000,0000,,这是每个地区在危机期间
Dialogue: 0,0:07:05.61,0:07:08.66,Default,,0000,0000,0000,,采取不同货币政策时的
Dialogue: 0,0:07:08.66,0:07:10.24,Default,,0000,0000,0000,,关键时期
Dialogue: 0,0:07:10.24,0:07:14.35,Default,,0000,0000,0000,,最右边的一栏报告了区内的变化
Dialogue: 0,0:07:14.35,0:07:20.46,Default,,0000,0000,0000,,第 6 区有 14  家银行倒下\N而第 8 区有 33 家银行倒下
Dialogue: 0,0:07:20.46,0:07:23.97,Default,,0000,0000,0000,,政策效果的数学公式很简单
Dialogue: 0,0:07:24.40,0:07:28.43,Default,,0000,0000,0000,,我们从第 6 区运营银行的变化中
Dialogue: 0,0:07:28.81,0:07:32.20,Default,,0000,0000,0000,,减去第 8 区运营银行的变化
Dialogue: 0,0:07:32.80,0:07:35.70,Default,,0000,0000,0000,,因而得名「双重差分法」
Dialogue: 0,0:07:37.00,0:07:41.74,Default,,0000,0000,0000,,-14 minus -33 equals 19.\]
Dialogue: 0,0:07:42.50,0:07:46.80,Default,,0000,0000,0000,,We estimate that 19 banks\Nwere saved by easy money.
Dialogue: 0,0:07:47.30,0:07:50.73,Default,,0000,0000,0000,,In practice, tables and figures\Nlike those shown here
Dialogue: 0,0:07:50.73,0:07:52.91,Default,,0000,0000,0000,,are the beginning\Nrather than the end
Dialogue: 0,0:07:52.91,0:07:54.45,Default,,0000,0000,0000,,of a DD analysis.
Dialogue: 0,0:07:55.40,0:07:57.10,Default,,0000,0000,0000,,The problem of how to gauge
Dialogue: 0,0:07:57.10,0:08:00.05,Default,,0000,0000,0000,,the statistical significance\Nof DD estimates
Dialogue: 0,0:08:00.05,0:08:02.26,Default,,0000,0000,0000,,turns out to be exceedingly tricky,
Dialogue: 0,0:08:02.26,0:08:05.60,Default,,0000,0000,0000,,and a regression is typically\Npart of the solution.
Dialogue: 0,0:08:09.20,0:08:12.34,Default,,0000,0000,0000,,The key assumption\Nbehind a valid DD analysis
Dialogue: 0,0:08:12.34,0:08:14.89,Default,,0000,0000,0000,,is that of parallel trends.
Dialogue: 0,0:08:15.37,0:08:17.84,Default,,0000,0000,0000,,Recall the principle\Nof ceteris paribus.
Dialogue: 0,0:08:17.84,0:08:20.92,Default,,0000,0000,0000,,Our ideal comparison\Nwould have the two districts
Dialogue: 0,0:08:20.92,0:08:24.02,Default,,0000,0000,0000,,experience an identical\Nbusiness environment,
Dialogue: 0,0:08:24.02,0:08:25.100,Default,,0000,0000,0000,,except for one factor:
Dialogue: 0,0:08:25.100,0:08:27.92,Default,,0000,0000,0000,,easy or tight money.
Dialogue: 0,0:08:29.20,0:08:32.35,Default,,0000,0000,0000,,Both districts would have\Nidentical types of customers
Dialogue: 0,0:08:32.35,0:08:35.30,Default,,0000,0000,0000,,who would go bankrupt\Nat exactly the same rate.
Dialogue: 0,0:08:35.70,0:08:38.60,Default,,0000,0000,0000,,The skill of their employees\Nwould be equal, and so on.
Dialogue: 0,0:08:39.20,0:08:43.50,Default,,0000,0000,0000,,Perfect ceteris paribus comparisons\Nwould allow us to clearly see
Dialogue: 0,0:08:43.50,0:08:46.59,Default,,0000,0000,0000,,the causal effect\Nof different Fed policies.
Dialogue: 0,0:08:46.59,0:08:49.02,Default,,0000,0000,0000,,In this case, that's not possible.
Dialogue: 0,0:08:49.02,0:08:53.60,Default,,0000,0000,0000,,But the idea of parallel trends\Nis based on a similar concept.
Dialogue: 0,0:08:53.60,0:08:57.36,Default,,0000,0000,0000,,If we see that the two regions\Nexperience similar trends
Dialogue: 0,0:08:57.36,0:08:59.65,Default,,0000,0000,0000,,in the number of banks over time,
Dialogue: 0,0:08:59.65,0:09:01.29,Default,,0000,0000,0000,,in the absence of treatment,
Dialogue: 0,0:09:01.29,0:09:04.41,Default,,0000,0000,0000,,we can assume\Nthey are good comparisons.
Dialogue: 0,0:09:04.41,0:09:07.43,Default,,0000,0000,0000,,We see that the two districts\Nmove in parallel,
Dialogue: 0,0:09:07.43,0:09:09.80,Default,,0000,0000,0000,,both before the crisis and after,
Dialogue: 0,0:09:10.10,0:09:12.40,Default,,0000,0000,0000,,when they have the same Fed policy.
Dialogue: 0,0:09:13.10,0:09:16.03,Default,,0000,0000,0000,,The only time the districts\Nbehave differently
Dialogue: 0,0:09:16.03,0:09:18.30,Default,,0000,0000,0000,,is when the Fed policy is different.
Dialogue: 0,0:09:19.40,0:09:20.60,Default,,0000,0000,0000,,In view of this,
Dialogue: 0,0:09:20.60,0:09:24.27,Default,,0000,0000,0000,,Fed policy is a likely cause\Nof diverging trends
Dialogue: 0,0:09:24.27,0:09:26.70,Default,,0000,0000,0000,,from 1930 to 1931.
Dialogue: 0,0:09:27.80,0:09:30.11,Default,,0000,0000,0000,,But we should also check\Nfor other changes
Dialogue: 0,0:09:30.11,0:09:31.70,Default,,0000,0000,0000,,unique to northern Mississippi.
Dialogue: 0,0:09:31.70,0:09:33.20,Default,,0000,0000,0000,,- [Man] Huh?\N- What do you mean?
Dialogue: 0,0:09:33.50,0:09:35.40,Default,,0000,0000,0000,,- [Teacher] Imagine that bad tornadoes
Dialogue: 0,0:09:35.40,0:09:39.10,Default,,0000,0000,0000,,hit northern but not\Nsouthern Mississippi in 1930.
Dialogue: 0,0:09:39.60,0:09:41.95,Default,,0000,0000,0000,,These tornadoes devastate farms,
Dialogue: 0,0:09:41.95,0:09:44.30,Default,,0000,0000,0000,,causing farmers\Nto default on loans,
Dialogue: 0,0:09:44.55,0:09:46.80,Default,,0000,0000,0000,,which drives their banks\Nout of business.
Dialogue: 0,0:09:47.40,0:09:49.44,Default,,0000,0000,0000,,Then the 6th and 8th districts
Dialogue: 0,0:09:49.44,0:09:52.27,Default,,0000,0000,0000,,would differ in not one\Nbut two ways:
Dialogue: 0,0:09:52.70,0:09:55.05,Default,,0000,0000,0000,,Fed policy and weather.
Dialogue: 0,0:09:55.05,0:09:58.22,Default,,0000,0000,0000,,And we'd have trouble\Nidentifying Fed policy
Dialogue: 0,0:09:58.22,0:10:01.59,Default,,0000,0000,0000,,as the causal factor\Nbehind increased bank failures
Dialogue: 0,0:10:01.59,0:10:02.60,Default,,0000,0000,0000,,in the 8th.
Dialogue: 0,0:10:02.60,0:10:04.25,Default,,0000,0000,0000,,- [Man] Ceteris is not paribus.
Dialogue: 0,0:10:07.20,0:10:09.01,Default,,0000,0000,0000,,- DD credibility lives or dies
Dialogue: 0,0:10:09.01,0:10:10.98,Default,,0000,0000,0000,,with the claim that the only reason
Dialogue: 0,0:10:10.98,0:10:13.79,Default,,0000,0000,0000,,northern Mississippi\Nwas special in 1930
Dialogue: 0,0:10:13.79,0:10:16.16,Default,,0000,0000,0000,,is differing regional Fed policy.
Dialogue: 0,0:10:16.60,0:10:20.53,Default,,0000,0000,0000,,We're in DD heaven with strong,\Nvisual evidence of parallel trend.
Dialogue: 0,0:10:21.28,0:10:25.55,Default,,0000,0000,0000,,- In general, the first step\Nin evaluating whether to use DD
Dialogue: 0,0:10:25.55,0:10:30.20,Default,,0000,0000,0000,,is usually this type of visual\Nconfirmation of parallel trends
Dialogue: 0,0:10:30.20,0:10:31.70,Default,,0000,0000,0000,,outside of the period,
Dialogue: 0,0:10:31.70,0:10:34.78,Default,,0000,0000,0000,,when we expect to see\Na treatment effect.
Dialogue: 0,0:10:35.09,0:10:36.98,Default,,0000,0000,0000,,The treatment in our example
Dialogue: 0,0:10:36.98,0:10:39.84,Default,,0000,0000,0000,,is easy money\Nin the face of bank failures.
Dialogue: 0,0:10:40.50,0:10:45.00,Default,,0000,0000,0000,,Metrics masters use DD\Nto explore effects of many policies,
Dialogue: 0,0:10:45.80,0:10:47.90,Default,,0000,0000,0000,,like the minimum legal drinking age,
Dialogue: 0,0:10:48.50,0:10:52.20,Default,,0000,0000,0000,,and environmental changes,\Nlike access to clean water.
Dialogue: 0,0:10:52.87,0:10:54.20,Default,,0000,0000,0000,,In our next video,
Dialogue: 0,0:10:54.50,0:10:57.04,Default,,0000,0000,0000,,we'll see an example\Nof how regression is used
Dialogue: 0,0:10:57.04,0:10:59.20,Default,,0000,0000,0000,,to implement a DD approach.
Dialogue: 0,0:11:00.80,0:11:02.18,Default,,0000,0000,0000,,- [Narrator] Are you a teacher?
Dialogue: 0,0:11:02.18,0:11:05.79,Default,,0000,0000,0000,,Click to explore ways\Nto use these videos in class.
Dialogue: 0,0:11:05.79,0:11:08.85,Default,,0000,0000,0000,,If you're a learner,\Nmake sure this video sticks
Dialogue: 0,0:11:08.85,0:11:11.20,Default,,0000,0000,0000,,by taking a few quick\Npractice questions.
Dialogue: 0,0:11:11.60,0:11:14.20,Default,,0000,0000,0000,,Or if you're ready,\Nclick for the next video.
Dialogue: 0,0:11:14.60,0:11:17.09,Default,,0000,0000,0000,,You can also check out\NMRU's website
Dialogue: 0,0:11:17.09,0:11:20.19,Default,,0000,0000,0000,,for more courses,\Nteacher resources, and more.
Dialogue: 0,0:11:20.19,0:11:21.69,Default,,0000,0000,0000,,♪ [music] ♪