price multiplier approach只反映了历史数据，这个不是乘数法的弊端吗？为什么是错误的呢？
问题如下图：
选项：
A. 
B. 
C. 
解释：
NO.PZ2015122802000174 问题如下 analyst makes the following statement: \"Use of P/E another multiples for analysis is not effective because the multiples are baseon historicta anbecause not all companies have positive accounting earnings.\" The analyst’s statement is most likely: A.inaccurate with respeto both historicta anearnings. B.accurate with respeto historicta aninaccurate with respeto earnings. C.inaccurate with respeto historicta anaccurate with respeto earnings. A is correct.The statement is inaccurate in both respects. Although multiples ccalculatefrom historictforecastevalues cusewell. For companies without accounting earnings, severother multiples cuse These multiples are often specific to a company’s instry or sector aninclu price-to-sales anprice-to cash flow.考试PriMultiple Approach题干说的是使用乘数效果不好是因为它只能用历史数据计算得到。这显然是错的，乘数可以基于历史数据也可以用未来财务数据计算得到。此外，题干说的是PE和其他乘数，当earning为负的时候都不可以用，这也不对，PE不能用，但不代表其他乘数不能用。 讲义里面说common criticism of all mutiples是 not consir the future. 为什么题干里面说的只用了historicta是错的。
NO.PZ2015122802000174 问题如下 analyst makes the following statement: \"Use of P/E another multiples for analysis is not effective because the multiples are baseon historicta anbecause not all companies have positive accounting earnings.\" The analyst’s statement is most likely: A.inaccurate with respeto both historicta anearnings. B.accurate with respeto historicta aninaccurate with respeto earnings. C.inaccurate with respeto historicta anaccurate with respeto earnings. A is correct.The statement is inaccurate in both respects. Although multiples ccalculatefrom historictforecastevalues cusewell. For companies without accounting earnings, severother multiples cuse These multiples are often specific to a company’s instry or sector aninclu price-to-sales anprice-to cash flow.考试PriMultiple Approach题干说的是使用乘数效果不好是因为它只能用历史数据计算得到。这显然是错的，乘数可以基于历史数据也可以用未来财务数据计算得到。此外，题干说的是PE和其他乘数，当earning为负的时候都不可以用，这也不对，PE不能用，但不代表其他乘数不能用。 1 如果是对于trailing multiple的话，用的历史数据；但用leang 指标，是反映了未来的。2 PE ratio的确是当earning小于0时，不可用。这题关键词在于other multiples吗？ 比如 PB ratio、 PS ratio，当earning小于0时，可用。所以选择A吗？
accurate with respeto historicta aninaccurate with respeto earnings. inaccurate with respeto historicta anaccurate with respeto earnings. A is correct. The statement is inaccurate in both respects. Although multiples ccalculatefrom historictforecastevalues cusewell. For companies without accounting earnings, severother multiples cuse These multiples are often specific to a company’s instry or sector aninclu price-to-sales anprice-to cash flow.课件里不是写价格乘数的缺点是只能看历史数据不能考虑将来的情况吗
我想问一下导致P/E not effective的原因是什么？
答案是什么意思？？？？………
