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Background Extensive evidence supports mechanical thrombectomy using stentrievers (SR) for acute large vessel occlusion (aLVO). Aspiration is also used as a first pass or adjunct technique during clot removal. Here we report technical results from mechanical thrombectomy cases using SR alone, aspiration alone (AD), or a combination of SR and aspiration (SA) as a first pass for aLVO. Methods An institutional stroke database was reviewed for patients presenting to a single academic institution with anterior circulation aLVO and who were treated with mechanical thrombectomy from 2011 to 2017. Patients managed with SR alone, AD, or a combination of these 2 techniques (SA) were identified. The rate of successful recanalization after the first thrombectomy attempt was compared between the 3 groups. Results A total of 353 patients were analyzed, including 215 in SR, 32 in AD, and 106 in SA groups. There was no significant difference for age and admission National Institutes of Health Stroke Scale between the groups. Successful recanalization rates after the first pass were 35.8% in the SR group, 34.4% in aspiration as a first pass technique, and 55.7% in SA, with a statistically significant higher rate of first pass success in the SA group (P = 0.002). Using balloon-guide catheter doubled the rate of successful first pass recanalization from 21.3% to 41.6% in the SR group (P = 0.005); however, the SA technique was more effective for first pass recanalization when compared with an SR and balloon-guide catheter combination (55.7% vs. 41.6%, P = 0.025). Conclusions The combination of SR and catheter aspiration can increase the rate of single pass successful recanalization compared with these techniques individually.

This study comes from my dissertation on the evaluation of student writing. I think I cared and still care about that topic because when I reached a stage where I consciously wanted to write better (I think not until I was an M.A. student in English literature at The University of Chicago), I realized that what was stopping me and what had always stopped me from being able to improve my writing was my inability to articulate what made some pieces I wrote better than others. And my teachers’ comments never seemed to help me very much. By studying texts and teachers’ judgments, I thought, I would be able to find some clues to what good writing was.

Richard Weaver is probably the foremost spokesman for another, more fundamental argument against borrowing from other disciplines, one that goes considerably beyond the observation that people may borrow without sufficient understanding. His argument concerns scientism, “the application of scientific assumptions to subjects that are not wholly comprised of naturalistic phenomena”, such as the humanities. MANOVA looks for main effects and interactions of the independent variables on the dependent variables as a group. When a MANOVA produces a significant result, the researchers can conclude that the independent variables have influenced the dependent variables in some way. Applying the Duncan test, Beach and Wendler found a significant difference in “act inferences” between eighth and eleventh graders, and between both eighth and eleventh graders and college students, but they found no difference between college freshmen and college juniors.

This chapter discusses people’s abilities to think about their own mental activities. Much of the research on metacognition has focused on metacognitive knowledge. People demonstrate metacognitive knowledge when they can accurately describe their own cognitive processes. To understand metacognition fully, one also needs to attend to what is called metacognitive skill, that is, to people’s ability to exercise deliberate control over their own cognitive activities. It is clear, though, that the contrast between what children do when they are asked to write well and what they do when they are asked to write badly is a very sensible and appropriate measure of deliberate metacognitive control of writing skills. The idea of metacognitive skill is a very important one, not just in the primary grades but for adult writers as well. In the late 70’s, the plain speech movement operated on the assumption that good writing is writing that conveys its message as simply as possible.

The simple design using random assignment of the test and control groups and only one treatment and one day to carry it out enabled them to control for such sources of confounding as concurrent events and maturation, testing effects, sampling bias and drop outs. The researchers’ account of how their thinking changed after the original research design had been completed reveals two processes which are quite common in the evolution of research projects. First, as it became more evident that the study would have a reportable outcome, the researchers became more active in considering how the audience might evaluate the study. Second, when the researchers collected their data, it didn’t look quite as they had expected. The assumption lead them to believe that the appropriate way to assess coder reliability would be to use the familiar Spearman rank order correlation.

The brainstorming research has compared individual generation of ideas and group generation, with the relative efficacy of group generation being called into question. In contrast, research has shown that cooperative learning not only facilitates academic achievement but has the potential for improving individual learning as well. The basic idea behind covariate analysis is this: Suppose that the researchers know that some variable of interest, say, writing quality, tends to increase as the the writer’s SAT-Verbal score increases. Thus, the researchers can calculate how well each student did in comparison to how well that student would have been expected to do on the basis of his or her SAT-Verbal score. Covariates can be used to estimate what the difference in performance between the two groups would have been if they had had equal SAT-Verbal scores.

This chapter presents Sarah Warshauer Freedman on two topics, one written for College Composition and Communication and the other for the Journal of Educational Psychology. Freedman describes a study of factors which influence teachers’ judgments of student papers. Although the two articles describe the same study and have the same general organization, they have different audiences and different purposes. The differences in rhetorical stance between these two papers—describing conclusions to practitioners versus arguing for their validity to empirical researchers—are reflected in important structural differences between the papers. The purpose of analysis of variance is to help in drawing conclusions in situations such as this: Suppose that have conducted a study on the vocabulary size of ninth through twelfth grade male and female students. Freedman used analysis of variance to assess the impact of four independent variables, content, organization, sentence structure, and mechanics, on the dependent variable.

Teaching experiments carried out in school settings, as was the case with George Hillocks’ project, offer researchers far more than their usual share of difficulties. Student’s interests are drawn to many things more important to them than the researchers’ concerns: sports, friendships, romance, pressures from home. In addition, practical requirements of classroom management may seriously restrict the time that is available for research or force the researcher to present one treatment to a whole class rather than randomly assigning students within classes to treatments. Hillocks’ study is a model of how to manage a teaching experiment in a complex school environment. Although he had only ten independent observations, his methods of design and analysis allowed him to make very effective use of them. School time is valuable and alternative instructional activities are in competition for the available time.

This study began as a conversation. As we tossed around some ideas for doing a study together, Dick (John Richard Hayes) and I found a mutual interest in task definition. The effect of task definition on revision was one of the items on Dick’s list of research issues waiting to be investigated. Dick’s interest had been piqued by an earlier study that had been abandoned and some previous work on revision (Hayes, Flower, Schriver, Stratman, & Carey, 1987) that had called attention to substantial differences between the basic approaches and strategies that expert and novice writers brought to revision. For me, the question was largely one of application. Given the differences between experts’ and novices’ basic understanding of revision, what should the reseacher do about it? We decided that we wanted to try to nail down the impact of task definition on teaching revision; over the course of a couple meetings we set up a simple experiment.