I recommend time-boxing how much time candidates will have to spend on your process. People coming from an alternate career path still have to pay their bills through their current job and tend to the same responsibilities as anyone else. Asking them to do days of unpaid homework (https://news.ycombinator.com/item?id=16874015) may not be a luxury they can afford.

For the take-home portion of your assessment, consider paying the candidates for their time at an entry-level annualized salary. Many companies would balk at this idea because it is more expensive, but it demonstrates respect for the candidate.

Looking at the website, I don't see many details about what the assessment actually includes. I think it would help to be forthright about the structure of the assessment. Does Hatchways or the employer determine what the assignment is? How does one create a rubric for scoring a submission, and how is quality assurance conducted on the effectiveness of these rubrics?

I think it is only fair to tell candidates what area of expertise they are going to be tested on a week ahead of time, so they can prepare as they see fit. As for this bit: "ability to follow a spec, code quality and how quickly the task is completed" - it would make sense that different companies would place different weights on each of these factors, given that some of these parameters can often be at odds with each other.

Also - a particularly tricky area: how do you give feedback to candidates? Do you help them succeed? Is it enough that Hatchways gives the feedback, and not the employer to avoid lawsuits? Having done some take-homes in the past that were rejected, I received absolutely no feedback on what could have been done better or what was missing. Candidates who continually to struggle and don't pass any of the interviews aren't necessarily morons or inept - they just need someone to point them in the right direction.