Pre-post Design
Pre-post Design - Related Videos
01:28
Cardiomyopathy VII: Pre and Post Operative Nursing Management
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2025
Patients with hypertrophic cardiomyopathy (HCM) and left ventricular outflow tract (LVOT) obstruction who remain symptomatic despite optimal medical therapy may undergo a septal myectomy (Morrow procedure). This procedure involves excising a portion of the hypertrophied septum below the aortic valve using a heart-lung machine to improve blood flow through the LVOT. Effective preoperative and postoperative nursing management ensures successful patient outcomes, minimizes complications, and...
08:13
Simultaneous Pre- and Post-synaptic Electrophysiological Recording from Xenopus Nerve-muscle Co-cultures
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Cited by 2 •
2013
This video demonstrates the procedures used to grow primary cultures of embryonic Xenopus nerve and muscle cells and the usefulness of this preparation for making simultaneous pre- and post-synaptic patch clamp recordings.
02:01
Group Design
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2020
The most basic experimental design involves two groups: the experimental group and the control group. The two groups are designed to be the same except for one difference— experimental manipulation. The experimental group gets the experimental manipulation—that is, the treatment or variable being tested—and the control group does not. Since experimental manipulation is the only difference between the experimental and control groups, we can be sure that any differences between the two are due to...
01:35
Pre-mRNA Processing: Modification of pre-mRNA Ends
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2023
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA. Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
11:27
The Use of Pharmacological-challenge fMRI in Pre-clinical Research: Application to the 5-HT System
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Cited by 8 •
2012
The goal of this technique is to assess serotonin (5-HT) neurotransmitter function in the live and free-breathing animal with pharmacological magnetic resonance imaging (phMRI) and an intravenous challenge with a selective serotonin reuptake inhibitor (SSRI), fluoxetine.
FAQs
Pairing observations lets researchers calculate how much each participant or unit changes rather than relying only on differences between separate groups. This within-unit comparison accounts for some individual variation, which can make shifts in outcomes easier to examine. The resulting differences support assessment of treatment effects, behavioral changes, or clinical outcomes.
History, maturation, and other unmeasured factors can alter outcomes between the baseline and follow-up observations. A change after an intervention therefore does not automatically show that the intervention caused it. Researchers must consider whether external events, natural development, or other influences could explain part or all of the observed difference.
A comparison group provides an additional reference for interpreting changes over the same period. It helps researchers judge whether the measured shift is more consistent with the intervention or with factors affecting units more broadly. This context strengthens interpretation beyond the within-unit change alone, especially when outside influences may affect follow-up outcomes.
Consistent timing makes baseline and follow-up observations more comparable, while consistent measurement reduces differences caused by changing how outcomes are assessed. If assessment conditions or measurement procedures vary, the observed change may reflect those inconsistencies instead of a genuine shift. Careful scheduling and repeated use of the same measurement approach improve interpretability.
Researchers should identify the units to be followed, establish a baseline observation, apply or document the intervention or exposure, and collect a follow-up observation after a specified period. They should also plan consistent timing and measurement procedures. Including an appropriate comparison group can provide stronger context for interpreting the resulting within-unit differences.
This framework is useful when researchers need to examine change in the same participants or units after treatment, exposure, or a defined period. It can support studies of treatment effects, behavioral changes, and clinical outcomes. Its main contribution is showing how outcomes shift within units, while its limitations require cautious interpretation of causation.