【问】 我从辞典上知道，more often than not=经常，往往，大半。但是，我却无法分析这个结构。

【答】 根据CGEL的解释，not在这里起着代分句的作用，它引导的从句是一个否定的比较从句：

He was found out more often than not.=More often than he was not found out. (DAI)

他经常被发现有错误。

类例：

1. Ben is a fairly good runner，he wins more often than not. (DAI)

本是不错的赛跑运动员，他常常取胜。

2. More often than not，we lay awake all night.

我们经常通宵不眠。

3. More often than not conservative people look backward rather than forward.

保守的人们往往不是向前看，而是往后看。

对more likely than not(很可能)，也应当作这样的分析。

She was satisfied with her job more likely than not. (CGEL)

她很可能对她的工作很满意。