Stata and SQLite

Stata and SQLite For those familiar with SQL, Stata’s lack of SQL support (apart from ODBC) can be perceived as a problem. However, Stata’s integration with Python offers a solution. Here are examples with one Stata script for exporting data to an SQLite database and another one for querying an existing SQLite database. In each… Continue reading Stata and SQLite

Observational or experimental?

Observational or experimental? Findings from confirmatory randomized trials are generally considered to represent a higher level of evidence than findings from observational studies. Manuscripts presenting randomized trials usually get more favourable evaluations and have lower chances of being rejected. Many authors of observational studies have recognized this phenomenon and try to use the knowledge in… Continue reading Observational or experimental?


HARKing It is quite easy to get a manuscript accepted in a scientific journal if only a few basic requirements are met, i.e. a reasonably interesting research question, a sound study design, and generally acceptable results. Unfortunately, the chance of succeeding with this in a randomised trial is not great. Randomised trials are expensive, time-consuming,… Continue reading HARKing


Associations Two variables are associated, statistically dependent, if one of the variables says something about the other, and this can range from nothing to everything. Correlated variables are always dependent, but dependent variables are not necessarily correlated because correlation refers to linear relationships. It is, for example, easy to show that the two mathematically coupled… Continue reading Associations


pdfgrep It is important to check the statistical terminology in manuscripts as this often reveals confusion and misunderstandings. However, the terminology is often not prioritized by reviewers, and corrections are not always appreciated. Nevertheless, the ideal scientific writing is clear, specific, and unambiguous. The reader does not have to guess what the author really means,… Continue reading pdfgrep

Review outcomes

Review outcomes When having reviewed a manuscript, the reviewer is often requested to provide the editorial office with a summary recommendation of the manuscript. The alternatives are usually accept minor revision major revision reject and resubmit reject The exact alternatives and definitions of the alternatives differ between editorial offices, but the recommendations accept and reject… Continue reading Review outcomes

Experimental and observational studies

Experimental and observational studies The statistical analysis of a dataset is always dependent on how the data have been collected. An experimental study, e.g. a randomised clinical trial, can be designed in such a way that validity problems (selection bias, misclassification bias, confounding bias) are prevented, for example using concealed treatment allocation, randomisation of patients… Continue reading Experimental and observational studies


Terminology In order to communicate without misunderstandings, it is important to realise that in contrast to spoken language, a combination of words; gestures; facial expressions; and with possibilities for immediate questioning and correcting, written language relies entirely on usage of the right words and compliance with the grammatical rules for combining these into understandable sentences… Continue reading Terminology


reMarkable I started reviewing manuscripts on paper, but the manuscript handling was soon digitalised and manuscripts distributed via email. At first, I found it difficult to read manuscripts on screen. I printed out the manuscripts on a laser printer, but the waste of paper was substantial. After many attempts, I eventually got used to reading… Continue reading reMarkable


Reviewing It is commonly believed that the line between knowledge and ignorance is clear and that scientific research systematically expands knowledge by reducing ignorance. However, what we think we know is a mixture of facts and beliefs. Here I use the term fact to describe something that is based on empirical evidence and has been… Continue reading Reviewing