I'm happy to comment on that.
I will say this issue specifically is difficult to quantify, but we found a 2016 survey that found that 47% of early-career health researchers considered moving abroad. Since then, conditions have worsened.
According to the OECD, Canada is second-last in the G7 for investment in research and development by percentage of GDP. What's also important to note is that these graduate students and post-doctoral researchers conduct research in post-secondary education and help with Canada's prestige and reputation in terms of academia.
However, 75% of these Ph.D. students end up in industry. These are the people who create the solutions to challenges like fighting climate change and tackling Canada's housing crisis. We need these people in research and private industry to tackle the challenges we're going to face as a country. If they are going elsewhere, other countries will benefit from the time and effort Canada put into educating these scientists.