Other types of documents

Letters 

Letters, or communications as they are sometimes called, are written for many reasons. You many want to provide supporting information, clarification, criticism, correction, or an alternative explanation to the results in a previously published journal article. You may disagree with the interpretation of the results, have further information to add to a publication, or have a novel comment to make. Many journals also publish letters that convey political or psychosocial messages that are related to the practice of medicine or research. 

Editorials 

The best editorials are usually short, pithy, pertinent reviews about a topic that is selected by the editor. An editorial is often commissioned to comment on a paper that is published in the same issue of the journal. Very often, the editor asks an external reviewer who has shown insight into the paper to write this type of timely review. 

Narrative reviews 

Review articles are very popular with readers and editors.Very short reviews are often called annotations. Editors likereviews because they know that, along with the editorials and the correspondence columns, they are the most widely read part of a scientific journal. To maintain reader interest, review articles must be topical, up to date, accurate and authoritative, and, if possible, provocative and a good read.

Systematic reviews and Cochrane reviews

Systematic reviews are a more rigorous compilation of evidence from the literature than narrative reviews simply because the search strategy for finding and summarising studies is clearly defined. In a systematic review of the literature, all of the primary studies on a topic are systematically identified, critically appraised, and summarised, with explicit and reproducible methods. The rationale behind this approach is that the standardisation and the transparency of the methods used by authors and the acquisition of all available primary studies on the review topic minimise the potential for bias. 

Case reports 

Most clinical journals publish case reports that explain how patients presented for medical care, how the course of the illness rogressed, and what treatment was given. Case reports that publish this information for a number of patients are called case series. The main purpose of a case report is to educate clinicians about the clinical features, investigation, and/or the treatment of patients with unusual problems. A case report often acts as refresher training for clinicians so that a diagnosis is made more readily and the condition treated more effectively. In reporting observations by clinicians, case reports may also generate hypotheses that lead to new research studies. 

Post-graduate theses

Postgraduate theses, whether they are for a doctorate or masters degree, command a huge time and motional commitment. The required length of a postgraduate thesis may vary widely but, for a doctorate, the range is generally 35 000–50 000 words with an upper limit often set at 80 000 words. If you are unsure how long your thesis should be, check with your institutional guidelines. Whether 40 000 or 80 000 words are used, writing a thesis is a long and daunting task and it may not become satisfying until the end is in sight.
However, if you write with a plan in mind, the process will be more rewarding.