School of Information Systems and Technology, Claremont Graduate University, Claremont, CA 91711, USA.
Int J Med Inform. 2010 Jun;79(6):438-49. doi: 10.1016/j.ijmedinf.2010.02.002. Epub 2010 Mar 4.
Willingness and ability to learn from health information in text are crucial for people to be informed and make better medical decisions. These two user characteristics are influenced by the perceived and actual difficulty of text. Our goal is to find text features that are indicative of perceived and actual difficulty so that barriers to reading can be lowered and understanding of information increased.
We systematically manipulated three text characteristics, - overall sentence structure (active, passive, extraposed-subject, or sentential-subject), noun phrases complexity (simple or complex), and function word density (high or low), - which are more fine-grained metrics to evaluate text than the commonly used readability formulas. We measured perceived difficulty with individual sentences by asking consumers to choose the easiest and most difficult version of a sentence. We measured actual difficulty with entire paragraphs by posing multiple-choice questions to measure understanding and retention of information in easy and difficult versions of the paragraphs.
Based on a study with 86 participants, we found that low noun phrase complexity and high function words density lead to sentences being perceived as simpler. In the sentences with passive, sentential-subject, or extraposed-subject sentences, both main and interaction effects were significant (all p<.05). In active sentences, only noun phrase complexity mattered (p<.001). For the same group of participants, simplification of entire paragraphs based on these three linguistic features had only a small effect on understanding (p=.99) and no effect on retention of information.
Using grammatical text features, we could measure and improve the perceived difficulty of text. In contrast to expectations based on readability formulas, these grammatical manipulations had limited effects on actual difficulty and so were insufficient to simplify the text and improve understanding. Future work will include semantic measures and overall text composition and their effects on perceived and actual difficulty.
These results are limited to grammatical features of text. The studies also used only one task, a question-answering task, to measure understanding of information.
从文本中的健康信息中学习的意愿和能力对于人们获取信息和做出更好的医疗决策至关重要。这两个用户特征受到文本感知和实际难度的影响。我们的目标是找到能够指示感知和实际难度的文本特征，以便降低阅读障碍并提高对信息的理解。
我们系统地操纵了三个文本特征，即整体句子结构（主动、被动、外置主语或主语从句）、名词短语复杂性（简单或复杂）和功能词密度（高或低），这些特征比常用的可读性公式更能精细地评估文本。我们通过让消费者选择最简单和最难的句子版本来衡量句子的感知难度。我们通过提出多项选择题来衡量整个段落的实际难度，以衡量对简单和困难版本段落中信息的理解和保留程度。
基于一项涉及 86 名参与者的研究，我们发现低名词短语复杂性和高功能词密度导致句子被感知为更简单。在被动、主语从句或外置主语句子中，主效应和交互效应均显著（均 p<.05）。在主动句中，只有名词短语复杂性起作用（p<.001）。对于同一组参与者，基于这三个语言特征对整个段落进行简化仅对理解有很小的影响（p=.99），对信息保留没有影响。
使用语法文本特征，我们可以衡量和改进文本的感知难度。与基于可读性公式的预期相反，这些语法操作对实际难度的影响有限，因此不足以简化文本并提高理解。未来的工作将包括语义度量和整体文本构成及其对感知和实际难度的影响。
这些结果仅限于文本的语法特征。这些研究还仅使用了一项任务，即问答任务来衡量对信息的理解。
