In this next module, we're going to talk about parallelism, which means writing sentences in parallel structure. Pairs of ideas that are joined by "and", "or" or "but" should be written in parallel form. That means that the two parts have to follow the same grammatical structure. Here's an example. The velocity decreased by 50 percent, but the pressure decreased by only 10 percent. So we've got subject-verb - velocity-decreased and then subject-verb - pressure-decreased. I'm gonna refer you here to another good writing reference. I borrowed this example from the "Essentials of Writing Biomedical Papers" by Mimi Zeiger. This is an excellent reference that's specifically on scientific writing, so I'll just point that out to you now. Here's another example of pairs of ideas that are joined by "and," "or" or "but." You would say "We aimed to increase the resolution and to improve picture quality." So we get infinitive phrase and infinitive phrase. Those pairs of ideas must be written in parallel form like this. Besides pairs of ideas, lists of ideas also need to be written in parallel form. This means that all items in the list should have the same grammatical structure. Here's another example from Strunk and White. The first version is not parallel. It says "Locusts denuded fields in Utah, rural Iowa was washed away by torrents, and in Arizona the cotton was shriveled by the placing heat". That's unparallel because all the items in the list have different constructions. "Locusts," "denuded," that's subject-verb; "rural Iowa was washed away," that's in the passive voice; "in Arizona," that's a propositional phrase. To make this sentence parallel, you can make all the items in the list follow subject-verb. So you can say "Locusts denuded fields in Utah, torrents washed away rural Iowa, and blazing heat shrivel Arizona's cotton." All of those follow subject-verb. Parallel is a means that you have to make a choice for the structure and stick with it. Here is an example of a sentence that's nicely in parallel structure. It says "NASA's intrepid Mars rover, Curiosity, has been through a lot in the past year. It flew 354 million miles, blasted through the Mars atmosphere, deployed a supersonic parachute, unfurled a giant sky crane, and touched down gently on the surface of Mars." Notice that in that second sentence, it's got a list of things - and they're all parallel. They all follow the same structure. We've got it flew, blasted, deployed, unfurled and touched down. So everything in that list starts with a verb. Also notice the really nice verbs in this sentence; it flew, it blasted, it deployed, it unfurled, touched down gently. Those are lovely verbs. Here's another example of a sentence that's not in parallel form. "If you want to be a good doctor, you must study hard, critically think about the medical literature, and you should be a good listener." You can hear that that sounds funny when you read it out loud. The first two items in the list are verbs; study and think, but the placement of the adverb is different. The final item in the list actually shifts from a "you must" to a "you should be." To make these parallel, you could make them all imperative. You can say "If you want to be a good doctor, you must study hard, listen well and think critically about the medical literature." Or you can also make them all into nouns. You can say "If you want to be a good doctor, you must be a good student, a good listener and a critical thinker.". All right. Another example of an unparallel sentence. "This research follows four distinct phases: (1) establishing measurement instruments; (2) pattern measurement; (3) developing interventions; and (4) the dissemination of successful interventions to other settings and institutions." Notice we've got "establishing" and "developing" - those match. But then we have "measurement" and "dissemination" - those two match, but all four don't match. To make them all match, we could turn them all into gerunds; that is, words ending in "I-N-G." So you could say "This research follows four distinct phases: establishing, measuring, developing and disseminating. When writing lists, always go back and double-check that your lists are parallel. This kind of mistake is quite common. I'm gonna do one practice example here. If you'd like to test yourself, you could pause the video now and attempt to get this into parallel structure on your own. Otherwise, I'll just lead you through it. This one reads "Bates describes the five principles for the success of decision support systems in clinical settings: speed, real-time delivery, integration into workflow, simplicity and to avoid data entry. You can hear the non-parallel structure when you read that one out loud. We have all nouns; speed, delivery, simplicity - until the last item, where we get an infinitive phrase - to avoid. This one's actually fairly simple to fix. You just have to turn everything into nouns. So you could say "Bates describes the five principles: speed, real time delivery, integration into workflow, simplicity and the avoidance of data entry. Now these are all nouns.