Here is how I would screen developers for a general developer position. I would issue a 1 hour limit and ensure the candidate knows the test is graded by a computer only. The goal is can they read instructions and write simple code. I don't care how they write the code. I only care that they can.
Any question could be as complex or challenging in requirements as necessary, but the answer would always be a small function of few parts. The idea being to test reading comprehension, the ability to follow instructions, and write a simple function. An example of output format and data type would be explicitly stated with each question.
An example question:
A customer is spending cash to purchase a drink. Write a function that receives cash as the first argument and the cost of the drink as the second argument and outputs an object indicating the change in coins with preference to the largest denominations first.
1. Specify the grading criteria of the test. 10 points for each question correctly answered within the given time period. There is no penalty for answering a question incorrectly. The cumulative total execution time of all answered questions will be multiplied by 100 if in milliseconds or by 100,000 if in nanoseconds and be deducted from the final score. The idea is to solve as many questions as possible, but in the event that there are a limited number of positions and tied scores slow code is the tie-breaker that disqualifies a candidate.
2. Stress that code style is irrelevant. The test will be graded by a computer compiling the code and executing it again several scenarios in an answer bank. A human will not review the answers submitted.
3. Tell candidates that once the 1 hour test period has exhausted they will have an optional 15 extra minutes to review all prior attempted questions.
4. Force the candidate to perform 3 practice questions before the test timer starts to familiarize the candidate the expectations of the test platform and the appropriateness of answers.
5. Randomly pull questions from a pool of 200+ questions 1 at a time to ensure a developer is focused on the question presented instead of selectively gaming the question list.
6. Ask the candidate to write a function in a designated space that addresses the problem question/statement.
7. Allow the user to test their answer to review the output before submitting it for the next question.
8. Also allow the user to skip to the next random question with a 2 minute time penalty.
That is for a developer. For an architect I would have them write an essay on a prompt provided by the business. Architects review business needs, distill requirements, and communicate goals to provide a platform that executes the business needs while minimizing complexity as much as possible. If they can do that in writing they can do it in software. The most important skill is their ability to communicate clearly against competing factors. Have 3 separate non-developers read and grade the essay.