I applied online for a data scientist position, recruiter contacted me and said they have another position for me. The hiring manager contacted after a week. I was asked some basic machine learning questions. Then he said for the next step I will be given a take home assignment to work on for a week, if we like your analysis we will ask you to present it on site. I worked on the problem and made hundreds lines of code. A lot of visualization and some predictive models. Then after submitting my work and following up multiple times they replied that they wish the analysis was more clear. Therefore they cannot move on to presentation. I am a PhD researcher in ML and I have years of experience with statistics. I believe they did not spent time to properly review my work and they probably are wasting time of many applicants like me. I found their process unethical to ask that amount of work from an applicant and don't letting them present or explain their position.