摘要: 'Research is about more than empirical evidence, but evidence at the heart of finding out social and education world. One way marshalling on a topic, or to answer research question, use findings others as published in literature. This third-hand common – notorious literature review for PhD, example. I say ‘third-hand’ because analyst does not have access primary nor are they re-presenting an analysis data. They presenting summary what previous author presented Done well, with clear focus, such can be useful, least establishing think, how topic usually researched, why might important further. Some inherent weaknesses using accounts overcome by ensuring that all relevant was used, even unsuccessful studies from unpublished studies, then conducting full meta-analysis results (I recommend Bayesian approach, see appendix Gorard et al. 2004, which allows relatively simple combination different kinds evidence). But systematic reviews rare, very difficult do properly, both expensive time-consuming. And anyway this second approach chief drawbacks we no direct others, often face partial view assumptions made analyses conducted.'