问题：

 List five limitations of learning curve theory. 

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答案：

 (i) The learning curve phenomenon is not always present. (ii) It assumes stable conditions at work which will enable learning to take place. This is not always practicable; for example, because of labour turnover. (iii) It must also assume a certain degree of motivation among employees. (iv) Breaks between repeating production of an item must not be too long, or workers will 'forget' and the learning process will have to begin all over again. (v) It might be difficult to obtain accurate data to decide what the learning curve is. (vi) Workers might not agree to a gradual reduction in production times per unit. (vii) Production techniques might change, or product design alterations might be made, so that it takes a long time for a 'standard' production method to emerge, to which a learning effect will apply.