Pay no attention to house price forecasts
Like those who tell the time from a stopped clock, the people who predict that British house prices will tumble will be right one day. But in the meantime, the rise continues and London estate agents are salivating at the prospect of City bonuses in January. Last week, the principal mortgage lenders announced that they would help new buyers by offering loans of five times income and 125 per cent of value.
If house prices have risen, so have the values of most other assets. Including the only asset category that really is safer than houses - long-term real government bonds. If the recently issued 50-year indexed stock had existed when Britain's housing boom began, almost 10 years ago, it would since have doubled in value. From that perspective, what has happened to house values is less remarkable.
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Asset bubbles emerge when the dominant motive for purchase is the expectation of selling on soon to someone else at a higher price. Such bubbles necessarily burst, because that expectation must sooner or later be frustrated. In this sense, there has never been a housing bubble except in certain, very limited areas of the market: the overwhelming majority of those who buy houses plan to live in them.
In the absence of bubbles, prices oscillate around uncertain estimates of fundamental value. These speculative prices typically display positive serial correlation in the short term - if prices have just gone up they tend to keep going up - and negative serial correlation in the long term - periods of above average increase are followed by periods of below average increase. If we knew when the short term became the long, we would all be rich, but we do not.
This pattern is one of mean reversion - prices return to a historic norm. For five years now, the expert consensus that British houses are overvalued has relied on one central fact - the ratio of house prices to incomes is at a historic high. But while there are some good reasons for expecting the price-earnings ratio of stocks to revert towards its long-term average, there are no similarly persuasive reasons for expecting the same of house prices. Houses are both an asset and a commodity and the analysis required is much more complex.
A house provides space and shelter and, in the American mid-west, these are the principal attributes of a house. There is more land there than anyone could build on and usually not much to choose between the prestige or convenience of different areas of the spacious cities. House prices are low, stable and tend to move in line with incomes.
London, Dublin or Barcelona, like Manhattan, California and Hawaii, are very different. Most of the price reflects the location rather than the accommodation. You cannot make more houses on East 69th Street or in Belgravia. Nor can you make more houses at the most prestigious addresses, because it is in the nature of prestigious addresses that there are not many of them.
Well located houses are what the economist Fred Hirsch called a positional good. House prices are consequently a product of sociology as well as economics. That combination explains why it is Britain, Ireland and Spain, not France, Italy and Germany, that have seen the fastest rises in European house prices and why Hawaii, California and New York, not Idaho, Mississippi and Nebraska, have been the hot spots in the US.
The aspirant rich do not displace the very rich from the best houses but they make the very rich pay more for them. This is the self-defeating character of the search for the symbols of status and affluence. So it goes on down the scale. The level of house prices depends not just on levels of income but on social mores and the distribution of wealth.
Successfully predicting house prices involves good economic models, an appreciation of the sociological dynamics of aspiration and a trader's flair for the waves of market psychology. Not many people combine these skills. My files tell me I wrote about house prices in 2001 and 2004 and concluded that the only information anyone offering confident predictions about house prices gave was that you should not pay attention to them. It is still true.
预测房价的人可信吗
就
像那些从停了的钟上读时间的人一样，预测英国房价将会下跌的人，总有一天会说对。但与此同时，房价依然在涨，伦敦地产经纪则对明年1月份金融城奖金所带来的前景垂涎欲滴。最近，主要抵押贷款银行宣布，它们会通过提供高出收入4倍的贷款，以及房价125%的贷款来帮助新买家。
如果房价上涨，那么大多数其它资产的价值也会上升。包括唯一一种确实比房屋更安全的资产类别――长期政府债券。如果最近发布的50年指数股票，在大约10年前英国房地产再次繁荣时就存在的话，那么自那时起这种债券的价值已翻了一倍。从这种角度而言，房价发生的变化，并不那么显著。
一旦买房的主要动机是期望尽快以更高价位出售给其他人，就会出现资产泡沫。这种泡沫必定破裂，因为那种期望定会迟早落空。从这个意义上讲，除了在某些非常有限的市场领域以外，从未有过住宅市场泡沫：买房的绝大多数人，都打算用于居住。
在无泡沫时期，对于基础价值有变幻无常的估值，而价格就在这些估值周围振荡。这种投机价格通常表现为，短期的正序列相关（如果价格已经上涨，则趋向继续上涨）和长期的负序列相关（高于平均涨幅的时期之后，跟随着低于平均涨幅的时期）。如果我们知道短期变为长期的时间，那么我们都会变富的，但是我们不知道。
这种形式是一种均值回归(mean reversion)――价格回归到历史均值。五年来，认为英国房价被高估的专家共识，取决于一个关键事实――房价与收入的比率，处于历史高位。但是虽然有一些很好的理由，期望股票的价格收益比率，向长期均值回归，但却没有类似有说服力的理由，期望房价发生同样的变化。房屋既是一种资产，又是一种大宗商品，它需要的分析要复杂得多。
房屋提供了空间和栖身之所。在美国中西部，那是房屋的主要特征。那里有的是土地，总多于建房的面积，而且对于那些地广人稀城市中的不同区域，在声望或便利方面，通常没有太多选择的余地。房价低、稳定，而且趋于与收入同向变化。
像曼哈顿、加利福尼亚和夏威夷一样，伦敦、都柏林或巴塞罗那就非常不同了。在很大程度上，价格反映地理位置，而非居住条件。你不能在纽约东69街或伦敦Belgravia区盖更多的房子。你也不能在最富声望的地段，盖更多的房子，因为享有声望的地段的本质就是物以稀为贵。
地点好的房子，是经济学家佛瑞德?赫希(Fred Hirsch)所称的位置商品。房价因此成了一种社会学和经济学的产物。这种结合解释了为什么英国、爱尔兰和西班牙出现了欧洲房价的最快增长，而不是法国、意大利和德国。它也说明了为什么夏威夷、加利福尼亚和纽约成了美国的热点地区，而不是爱达荷州、密西西比州和内布拉斯加州。
有抱负成为富人的人，没有将那些非常富有的人从最好的房子中挤出去，但他们让那些非常富有的人为房子付了更多的钱。这是寻求身份和富裕象征的自我拆台的特征。因此，这成比例缩减。房价水平，不仅取决于收入水平，还取决于社会风俗和财富分配。
要成功地预测房价，就要有良好的经济模型、对渴望这种社会动力的正确评价，以及交易员对市场心理波动的洞察力。没有多少人能集这些技能于一身。我的档案告诉我，我曾对2001年和2004年的房价作出评论，而我的结论是，如果有人自信能够提供房价预测，这一信息唯一能够告诉你的是，你不要理睬他。至今为止，这一观点依然正确。
