What does "bias" refer to in research?

Bias in research specifically refers to systematic errors that can affect the validity of study findings. When bias is present, it leads to conclusions that may not accurately reflect the true relationship or effect being studied, ultimately undermining the integrity of the research. This systematic error can result from various factors, such as how data is collected, analyzed, or interpreted, and is not simply random noise or variation in the data.

In contrast, subjective opinions on study design, financial conflicts of interest, and random variations in data do not fully encapsulate the concept of bias. While these may play a role in research quality or outcomes, they don't define bias in the context of systematic errors impacting validity. Therefore, understanding bias as a systematic error affecting validity is crucial for evaluating and interpreting research correctly.