The chapter argues that the process of premature closure of evidence collection and the thorough and objective collection of evidence and consideration of suspects is a root factor in many cases of miscarriages of justice. The chapter also considers how some of the measures designed to counter premature closure, such as formalized case review, have been imposed on the investigative process as a result of key cases of miscarriages of justice. An initiative under the British Police Reform Act 2002 was the Professionalizing the Investigative Process (PIP) program, which was formally launched by the Association of Chief Police Officers in 2005. The aim of PIP is to enhance the investigative process through training and development of those involved in criminal investigation. As indicated in the Core Investigative Doctrine, this is to be achieved by providing training in and assessment of professional investigative procedures designed to assist investigators in making accountable decisions and minimizing the chance of errors. The effectiveness of these and other attempts to improve investigations may fall short of their objectives, however, if they are not based on research efforts that address what constitutes a "good detective" and a "good investigation." Such research might focus on what went wrong in the investigation of known cases of miscarriages of justice. 42 references