This book provides a likelihood-based introduction to econometrics. In essence, the idea is to carefully investigate the sample variation in the data, then exploit that information to learn about the underlying economic mechanisms. The relative likelihood reflects how well different models of the data perform. We find this is auseful approach for both expository and methodological reasons.

The substantive context of econometrics is economics. Economic theory is concerned about how an economy might function and how agents in the economy behave, but not so much about a detailed description of the data variation that will be observed. Econometrics faces the methodological challenge that much of the observed economic data variability is due to factors outside of economics, such as wars, epidemics, innovations, and changing institutions. Consequently, we pursue a methodology where fairly general econometric models are formulated to capture the sample variation, with one or several economic theories being special cases that can be tested.

这本书提供了一个基于可能性的计量经济学的介绍。本质上，这个想法是仔细调查数据中的样本变化，然后利用这些信息来了解潜在的经济机制。相对可能性反映了不同模型的数据表现。我们发现这是一种有益的方法，既有解释性的原因，也有方法论的原因。

计量经济学的实质性背景是经济学。经济理论关注的是一个经济体如何运作，以及经济体中的主体如何表现，而不是对将要观察到的数据变化的详细描述。计量经济学面临着方法论上的挑战，即许多观察到的经济数据的可变性是由于经济以外的因素造成的，如战争、流行病、创新和制度变迁。因此，我们寻求一种方法，其中相当一般的经济计量模型被制定来捕捉样本的变化，其中一个或几个经济理论是可以检验的特例。