Reproducibility means that research data and code are made available so that others are able to reach the same results as are claimed in scientific outputs. Closely related is the concept of replicability, the act of repeating a scientific methodology to reach similar conclusions. These concepts are core elements of empirical research.
Improving reproducibility leads to increased rigour and quality of scientific outputs, and thus to greater trust in science. The concept of reproducibility is directly applied to the scientific method, the cornerstone of Science, and particularly to the following five steps:
Each of these steps should be clearly reported by providing clear and open documentation, and thus making the study transparent and reproducible.
Read more about reproducibility and its issues in The Academy of Medical Sciences' symposium report of 2015 on improving research practice. A quick view provided in the image from their report:
Everything is in the paper; anyone can reproduce this from there!
This is one of the most common misconceptions. Even having an extremely detailed description of the methods and workflows employed to reach the final result will not be sufficient in most cases to reproduce it. This can be due to several aspects, including different computational environments, differences in software versions, implicit biases that were not clearly stated, etc.
I don't have the time to learn and establish a reproducible workflow.
In addition to a significant number of freely available online services that can be combined and facilitate the setting up of an entire workflow, spending the time and effort to put this together will increase both the scientific validity of the final results as well as minimise the time of re-running or extending it in further studies.