What do you look for while hiring a junior PMM candidate, especially someone who might not have had a prior PMM experience? What assignments would you typically ask as part of recruitment?

1. writing skill: the messaging side of the marketing house, so you need to learn how to write. 
2. presentation skill: you're not just enabling sales, but also marketing so can you present your ideas succintly 
3. intellectual curiousity: you're task with taking new products to market or going into new segments. 

I would look at those three as the initial pillars to gage someone who is ready to be in PMM. 

I like people who stretch themselves and try, despite all of the challenges others may perceive against them. So, I'd ask myself how has this junior candidate tried to become a product marketer?

1. Have they read some books on product marketing and taking some courses (or gotten certifications)?

2. For me, writing is critical. Has this person studied writing in college, worked in journalism/blogging, or even written short stories?

3. If no one has given them an opportunity to do product marketing, have they volunteered to do product marketing for free for a small startup to get some experience? (I did volunteer marketing work when I was starting out with no savings — it was difficult and stressful but helped me land my first job in marketing.)

Product marketing is a relatively new and evolving discipline. Unlike traditional marketing roles, there's no specific educational path or degree that leads directly to a product marketing career. As a result, we often come from diverse backgrounds, bringing unique skill sets and perspectives to the table.
When hiring junior PMMs, especially those without direct experience, it's essential to recognize this and look for candidates who possess the fundamental skills and mindset that can be applied and developed in the context of product marketing. Here's what I prioritized:

1/ Can they tell a compelling story? Ask them to summarize a complex technical concept in simple terms for a non-technical audience. Or even have them tell a story about a product they like. Specifically evaluate if they can identify 2-3 key aspects of a product that can drive impact on a customer
2/ Can they work with cross functional stakeholders? Present a hypothetical scenario where they need to collaborate with sales, product, and design teams. Assess their ability to navigate different perspectives and build consensus. Ask about past experiences working with cross-functional teams, focusing on challenges they faced and how they overcame them.
3/ Can they identify the most critical tasks and focus their energy where it matters most? Give them a list of competing product marketing initiatives and ask them to prioritize them based on potential impact and available resources. Observe their thinking process (or)

Present a case study of a failed product launch and ask them to analyze the root causes, emphasizing the importance of prioritizing the right actions. It can be a common launch in the market as well.
4/ Can they truly understand and represent a customer? Ask them to create a customer persona for a target segment, detailing their pain points, motivations, and buying behaviors. It can be for a product they use. They need not have the right framework, but can they deeply understand a customer and their behaviors.
5/ [Optional] Can they understand what a business needs? Ask them to explain how they would measure the success of a product and how it might relate to a business outcome.

I recommend not looking for frameworks in their answers, but to understand if their thought process is in the right direction. Frameworks are coachable. Mindset is tougher.
And lastly, every PMM is a result of some manager taking a chance on them. Good luck in hiring !

Generally a great product marketer is built on three knowledge pillars: 

1. Market Knowledge
2. Product Knowledge
3. Marketing Knowledge

In the case of somebody brand new to product marketing, having just one of these would be fantastic. For junior roles, I'm selecting candidates based on their likelihood to develop these three areas of expertise. My go-to case assignment is asking the candidate to identify a market and segment, approximate its size, then craft a positioning statement and message for an offering to that audience. The instructions include a "time limit" and our positioning statement structure.

The real insight comes in the review of the prepared materials. I focus on "how" questions so I can better understand the candidates approach to each component. From a high-level I'm looking for indications of empathy for the market segment and their problem along with a reasoned approach to approximating the market size.