If you publish a protocol article or the statistical analysis of a study before the project is completed this will insure that you are not going on a fishing expedition in your data analysis. It is therefore good academic practice to stick to your pre-defined statistical analysis plan when doing your data analysis. A tool to ensure that is to publish a protocol article or to make your statistical analysis plan publicly available before you do the data analysis. Protocol articles may be published in several journals but most often only if your study is a large randomised human clinical trial.
It is technically easy to write a protocol article because you will use the study protocol as a starting point and the protocol article will of course not have a results section and the discussion section is kept quite short.
The most important thing in a protocol article is the section with the statistical analysis plan which will be much more detailed than in the actual trial protocol and of course much more detailed than the details given at for instance www.clinicaltrials.gov. In the statistical analysis plan in your protocol article you will indicate in detail which parameters you want to analyse, what you will compare them with and what tests you will use. Right down to the very tiny detail.
Some journals will publish protocol articles so you have to look in the instructions to authors or browse through recent volumes of the journals to find a good place for your protocol article.