According to the item/order hypothesis, high-frequency words are processed more efficiently and therefore order information can be readily encoded. In contrast, low-frequency words are processed less efficiently and the focus on item-specific processing compromises order information. Most experiments testing this account use free recall, which has led to two problems: First, the role of order information is difficult to evaluate in free recall, and second, the data from free recall show all three possible patterns of results: memory for high-frequency words can be better than, the same as, or worse than that for low-frequency words. A series of experiments tested the item/order hypothesis using tests where the role of order information is less ambiguous. The item/order hypothesis predicts better performance for high- than low-frequency words when pure lists are used in both immediate serial recall (ISR) and serial reconstruction of order (SRO) tests. In contrast, when mixed (alternating) lists are used, it predicts better performance for low- than for high-frequency words with ISR tests, but equivalent performance with SRO tests. The experiments generally confirm these predictions, with the notable exception of a block order effect in SRO tasks: When a block of low-frequency lists preceded a block of high-frequency lists, a high-frequency advantage was observed but when a block of high-frequency lists preceded a block of low-frequency lists, no frequency effect was observed. A final experiment provides evidence that this block order effect is due to metacognitive factors.

根据项目/订单假设，高频词的处理效率更高，因此订单信息可以很容易地编码。相比之下，低频词的处理效率较低，并且专注于特定项目的处理会损害订单信息。测试这个账户的大多数实验都使用了免费召回，这导致了两个问题：第一，订单信息在免费召回中的作用难以评估，其次，免费召回的数据显示了所有三种可能的结果模式：记忆力高-频率词可以比低频词更好、相同或更差。一系列实验使用订单信息的作用不那么模糊的测试来测试项目/订单假设。当在即时序列召回 (ISR) 和序列重构顺序 (SRO) 测试中使用纯列表时，项目/顺序假设预测高频词的性能比低频词更好。相比之下，当使用混合（交替）列表时，它预测低频词的性能比使用 ISR 测试的高频词更好，但与 SRO 测试的性能相当。实验大体上证实了这些预测，除了 SRO 任务中的块顺序效应的显着例外：当低频列表块在高频列表块之前时，观察到高频优势，但当高频列表块时-频率列表在低频率列表块之前，没有观察到频率效应。最后的实验提供的证据表明，这种块序效应是由元认知因素引起的。