The scientific method demands that researchers follow logical steps in their process to ensure that results are definitive. Without following these steps, including the proper design of experiments, the resulting data is not reliable. Over time, the research establishment has determined certain types of experimental designs, their advantages and disadvantages, as well as which type of design is appropriate for certain fields or contexts. Today we’ll get an overview of the types of experimental designs and how they impact the research conducted in healthcare infection control.
Not all scientific studies are created equal. Some studies are well-designed, with results that stand up to the intense scrutiny, analysis, and replication demanded by the scientific method. On the other hand, some studies are designed poorly, resulting in conclusions that can be called into question or that are not supported by the data. In this post, we explore two of the major ways that scientific studies are evaluated, giving you some tools to help in your own evaluation of the caliber research studies.
The two aspects of research quality we will discuss today are internal validity and external validity. First, let’s consider the word validity. A study is considered valid - from the Latin word for 'strong' - if it is strongly supported by facts and logic. In terms of scientific research, to have valid conclusions, a study must have a valid design. This brings us to internal validity.
Imagine a group of hikers setting out on a 100-mile trek through a remote forest, each taking their own path and traveling alone. Each carries a backpack with supplies necessary for survival such as water, food, tent, and first aid kit. However, a few of them also carry a survival handbook with instructions on how to survive in the wild during life-threatening situations. Unfortunately, this book is extremely heavy, adding 50 lbs the backpack. Who will arrive at the destination?
Discussion of the reduction of microorganisms in healthcare settings will often include the data as “log reductions.” To those of us more accustomed to percentages, this can be confusing. Today's post will explain how to interpret these numbers and, we hope, help our readers better understand how they are used in scientific literature.
An earlier version of this post was published in May 2015.
Sometimes a product comes along that breaks the paradigm. It is so innovative and unexpected that attempts to fit it into an existing market category are impossible. When that happens, a new category must be created to accommodate the new technology. This is the case with surfaces that actively kill bacteria. They're not a cleanser, per se. They're not really a device, either. What are they? Enter Preventive|Biocidal Surfaces.
Reports have been recently published of the first isolation and identification of the first colistin resistant bacteria in the US[i]. While we may be getting used to hearing of antibiotic resistance, this report indicates the last threshold on the pathway to complete antibiotic resistance being crossed.
On Memorial Day, we remember those men and women who died serving our country as a member of the armed forces. Traditionally, the day is set aside to remember those who died in combat. We add to that tradition today, remembering those who died fighting for our country, even as they lost the battle to war’s deadliest opponent: Disease.
An earlier version of this post appeared in July 2015.
Copper is the oldest-known metal used by humankind to make tools and decorations, helping form the transition from the Stone Age to the Bronze Age. After millennia of using wood, stones, and animal bones, copper transformed the abilities of early peoples, pushing them to invent ore smelting, mining, and metalworking. As a result of these skills honed over generations, cultures around the world took the next step, combining metal ores to create harder metals, such as bronze, a combination of copper and tin. What is special about copper, and how will it take us to the next level in healthcare safety?
An earlier version of this article was posted on September 15, 2016.
Remember those proofs from high school geometry? Based on given a set of rules, you could discover the measurement of all the angles in a shape from just one measurement. Stepping you way from that one measurement to the next, you could prove with certainly the measurement of another, then another, until all the angles were accounted for, each determination backed up by a known rule.
An earlier edition of this post was originally posted on December 8, 2014.
Bacteria rule the world. Not only do they far outnumber every other type of plant or animal, they are everywhere - inside and outside every other type of animal and in every conceivable environment, from boiling thermal vents to sub-zero glaciers. But not all bacteria are germs, or illness-causing bacteria. Most are vital to our survival and to the survival of life on Earth. Unfortunately, some bacteria are dangerous, especially to those of us with weak immune systems. Today’s post will explore this incredible branch of the tree of life, and our “can’t live with ‘em, can’t live without ‘em” relationship with these microorganisms.
What is bacteria?
Bacteria are single-cell organisms. Where humans are made up of, on average 1 trillion cells, bacteria are made up of just one. But one isn't the loneliest number when it comes to bacteria; they reproduce very efficiently by splitting into two, who then go on to split into two more… and on until you have a colony of bacteria. Some of these colonies are beneficial to us, some don't harm us at all, and some are downright nasty, leading to harmful infections which can threaten our lives.