How can improper methods, or a lack of systematic research create false beliefs about social reality?

Lack of proper research methods will inject false beliefs about the social reality through either assumption or bias.  When these influences are applied to sociological study the outcome becomes skewed in unpredictable ways and can further compound the problem by substantiating incorrect conclusions or beliefs.  The danger of relying on improper research is obfuscating the original problem with unrelated or non-existent tangents.

Assumption error occurs in research when researchers accept a key component of their model without properly verification.  Assumptions are a key part of research but need to be vetted and eliminated whenever possible.  For example, if a survey is taken of the public it may be assumed people are telling the truth.  Some research will allow for anonymous surveys to help reduce stigma attached to socially awkward questions.  The modifications is one manner the researcher can verify their assumption of truthfulness.  When a researcher fails to control for assumptions the assumptions often become confused with fact leading to false conclusions.

Bias error occurs when a bias or prejudiced is introduced into the research.  The error may be intentional or unintentional, but will result in skewed analysis based on inflated data sets.  Bias error can occur in any research step.  Once it occurs it will taint the remainder of the research.  When researching a social question, bias can limit the researchers view of the problem based on their own experience.  Narrow research will result in narrow data that can only be applied in specific circumstances rather than projected to a larger social reality. 

Bias error is one method which can also be intentionally used to create a false narrative.  When creating a survey, limiting the choices can introduce a bias and provide the researcher with information which appears to support their bias.  For example, suppose a question is aimed to determine whether you believe a transgender person should use the bathroom of their biological sex.  The answers you have to choose are "yes" or "no".  Although it seems benign, the bias is that those are the only or the best two options.   The data does not account for people who believe another restroom category should be created, or unisex bathrooms utilized, or family restrooms used.

Assumption error caused problems in research because it often creates unconnected questions or encourages research into irrelevant areas because false information was accepted as fact.  Bias error is the opposite and limits research because it forces data to conform to a predetermined belief or position.