Most management decisions are not based on the best available evidence. Instead, practitioners often prefer to make decisions rooted solely in their personal experience. However, personal judgment alone is not a very reliable source of evidence because it is highly susceptible to systematic errors – cognitive and information-processing limits make us prone to biases that have negative effects on the quality of the decisions we make. Even practitioners and industry experts with many years of experience are poor at making forecasts or calculating risks when relying solely on their personal judgment.

Practitioners frequently also take the work practices of other organizations as evidence. Through benchmarking and so-called  ‘best practices’ practitioners sometimes copy what other organizations are doing without critically evaluating whether these practices are actually effective and, if they are, whether they are also likely to work in a different context. Benchmarking can demonstrate alternative ways of doing things, but it is not necessarily a good indicator in itself of what would work in a different setting.

At the same time there are many barriers to evidence-based practice. Few practitioners have been trained in the skills required to critically evaluate the trustworthiness and relevance of the information they use and most practitioners pay little or no attention to evidence from the scientific literature or from the organization, placing instead too much trust in low-quality evidence, such as personal judgment and experience, ‘best practices’ and the beliefs of corporate leaders. As a result, billions of dollars are spent on management practices that are ineffective or even harmful to organizations, their members and their clients.