The Questions: Do students use more complicated sentence structures than practitioners do?  If so, what is the impact of the difference in sentence structure?

The Main Finding: Students DO use more complicated sentence structures than practitioners do. Students use more subordinate clauses and have more embedded grammatical structures in their sentences.

In a study of reports and tech memos, less than 25% of the practitioner sentences had embedded or subordinate clauses within a sentence, but over 50% of the student sentences did (Figure 1).  This difference was statistically significantly (χ2 = 3.93, df = 1, p < .05). 

Figure 1.  Sentences with subordinate clauses or embedded 
structures in reports and tech memos

Practitioner texts have simpler sentence structure with each sentence covering one idea.  Sentences can be long, but not because they have complex sentence structure. Instead, they are long because they make descriptions of locations, amounts, and objects very precise with long noun phrases and prepositional phrases (examples below). The information is dense even though each sentence typically expresses only one main idea.   The students, on the other hand, tend to write more sentences that are structurally complex, using subordinate and embedded clauses to cover multiple ideas in single sentences.  The information is less dense overall, and when the students use complex noun phrases, the nouns are more often abstract.

Here is an example comparing landslide descriptions:

Practitioner Writing

Student Writing

These characteristics of the student writing make information imprecise and make reading slow and confusing - major problems for engineering practice.