This is the story behind “Comparing process-based and constraint-based approaches for modeling macroecological patterns” by my former PhD student Xiao Xiao, James O’Dwyer, and myself. Background I was on sabbatical in the fall of 2013 and was doing a lot of reading, and I reread “An integrative framework for stochastic, size-structured community assembly” by James O’Dwyer, Jessica Green, and colleagues.