I am starting a PhD, and an interested in getting technical skills I will need over the next few years.
Are there any ethical issues with paying for people to help you to get these skills, assuming they are fully acknowledged?
From what I have read, I am working with the assumption that it is OK, as long as they are not "contributing to the research". However, this seems a bit fuzzy to me. Where does the boundary between the acceptable and unacceptable input lie?
In principle, as long as you give credit where credit is due, and as long as you do a thesis worth of work yourself, there need not be any problem. A nice example: many large biosciences have lab-specific technicians or technicians in share core facilities who carry out routine work and protocols. The student may not be paying them directly, but they are paid to do things for the benefit of the student's work (e.g., mouse colony maintenance, routine DNA preparation, sequencing, etc.) that may end up contributing to a thesis.
The specific examples of work that you want to outsource, however, are rather concerning. If you are working on computer algorithms, then you should be comfortable with basic data analysis, plotting, and programming. If you aren't, and need a tutor to help get your skills up to speed, that's fine. If you're outsourcing simple but non-routine analyses that you should be doing yourself, however, it's likely to introduce serious problems because you will not be in a good position to debug the problems that will arise during analysis. Furthermore, as a prospective future employer, it would also make me very concerned about your competence in your area of study.
In short: tutoring and outsourcing routine tasks if fine; outsourcing your core work is not.
As mentioned in your comment you are planning to ask help on data analysis and programming.
As you are a PhD student, not a project manager; you should ask your PhD advisor whether those chores are your duties or not. I mean, it may be part of your duty as a PhD student to do data analysis and programming, so asking someone else to do it for you will not be a good idea.
May be your PhD advisor has another PhD student or postdoc in his laboratory or research group and he may ask that person to help or teach you the programming and data analysis methods. He may decide that person to collaborate and do some parts of data analysis/programming for your project. May be he is expecting you to do those duties as part of your PhD programme.
Policies on your program and project also play important role in answering your question. You should make sure whether you are allowed to ask somebody to enter your project (even for short periods) or not.
Is it OK to get external help during your PhD if it is acknowledged?
My answer to your question is, I cannot say whether it is OK or not. It depends on your PhD program, your university/research institute's policies and expectations of your PhD advisers from you.
Of course, learning methods you need to do your project and asking somebody to teach these skills and methods to you is a good idea. You may ask someone to teach you programming or data analysis methods.
As a fellow PhD Candidate myself, here's something else to consider. In my field of study (social sciences) people often hire professional statisticians to run the analysis for their dissertations because they are "people persons" and don't like advanced math. They often want to go into counseling or something like that where knowing how to run a multinomial logistic regression isn't really useful for their day-to-day job. It's understood that this is a wide-spread practice. I, for one, enjoy research and I've made it a point to learn everything I can about the analysis for the simple fact that the analysis will be asked about during my oral defense. If I paid someone to "run the numbers" for me, would I be able to adequately explain what methods they used or what the results mean and why I came to those conclusions? I'd rather take the extra time and do it myself so that I understand every aspect of the analysis. I have seen several people bomb their defense for this reason.
If your PhD is in computer science or electrical engineering, it is expected that you can implement an algorithm in, say python or C++. Ask your advisor.
Once upon a time, a civil engineering, PhD student, friend told me he had discovered this approximation (optimizing a hill's shape/slope for erosion resistance). He asked me (a physics PhD) if I could help him justify the math in exchange for being the middle author. I agreed and spent 10s of hours learning about continuum mechanics, programming a boundary value problem, deriving math, and proofreading the draft. Everyone was very happy with the collaboration.
