The Improvement Experiment was an experiment performed by Michael, with the help of Gen and Janet (and eventual aid of Jeff) on Eleanor, Chidi, Tahani and Jason. It was the second in a series of experiments performed by Michael upon humans, the first one being his neighborhood experiment.
Over the course of Michael's original experiment, Neighborhood 12358W, Michael counted on the fact that Eleanor's selfishness would hold the experiment together. However, Eleanor managed to improve within the experiment, as did all of the other humans, fixing their initial flaws. When Michael began to improve, he realized that this must be the case of all humans–they all must be capable of improvement.
Originally, Michael and Gen had decided to put the four humans in Medium Places while they figured out the solutions. However, the humans disliked this solution, so Michael convinced Gen to begin a new experiment. He went to Earth and reversed the deaths of Eleanor, Chidi, Tahani and Jason to see whether or not they would improve. He and Janet were then able to monitor the humans' progress using omniscient ticker-tapes.
Timeline of Experiment Edit
The experiment lasted from Chapter 26 until Chapter 35 (because that's when the humans actually left Earth). Technically, however, the experiment was invalid after Chapter 31, and the results were already tainted during Chapter 29.
During Active Experiment Edit
In Chapter 26, Michael went to Earth and saved the lives of the humans, therefore starting up a new timeline. The humans each improved before being tempted back to their old ways, showing that the experiment, initially, failed.
In Chapters 27 and 28, Michael urged the humans to find each other so that their bond would become unbreakable. Although this technically was tainting the results, Michael was confident that their improvement was based on their bond, and that the fact that they didn't know anything about the afterlife would make up for their unity. The group formed to study the effects of near-death experiments on ethics, with the addition of Simone, who would monitor the brain scans.
In Chapter 29, Trevor joined the study group to try and split the humans apart. Michael and Janet showed up to stop him. Trevor tried to annoy Eleanor into leaving, convince Jason and Tahani to sleep together so that Tahani would leave, and trick Chidi into worrying about the ethics of fraternizing with the subjects of his study. Michael and Janet were able to stop Trevor from doing any more damage, and the group was able to heal itself on its own (Jason called a cab for Tahani to take her home, and Chidi went to convince Eleanor to stay, thereby proving that he was friends with her). Though the results were tainted, the study seemed ready to continue.
At this point, Michael and Janet's activities on Earth were discovered by Gen, so they fled the Afterlife to monitor the humans' progress on Earth.
In Chapter 30, Michael and Janet remained on Earth to remove any obstacle that could possibly prevent the group from improving. To prevent Jason and Tahani from sleeping together, they set Tahani up with her ex-boyfriend, Larry Hemsworth. Tahani and Larry got engaged and decided to move back to London, so Michael and Janet infiltrated the party and convinced Eleanor to ask the other members of the study to stay. When they don't reciprocate her desire, she lashes out and destroys the cake. Simone explains that she is feeling the loss of her first real group, and Eleanor apologizes to the other three. They go to get more champagne, and discover Michael and Janet discussing the nature of the Afterlife in front of the Door, which is open.
In Chapter 31, Michael explains the Afterlife system, thereby preventing the humans from earning points and effectively ending the experiment.
After Active Experiment Edit
During Chapter 31, the humans come to terms with their fate and decide to help others get into The Good Place.
During Chapter 32, Chidi breaks up with Simone so that he doesn't have to lie to her and Michael, Tahani and Jason help Pillboi by instructing him to remain at his job at the Old Folks' Home and do as much good for him as they can under the guise of "secret astronaut spies".
During Chapter 34, Michael proves to Eleanor that there is free will using memories from the Afterlife and iced tea, and eventually decides that they need to use a blueprint for how to live a good life.
During Chapter 35, Michael and Janet visit Doug Forcett and realize that he's become a happiness pump, so that he is miserable in his pursuit to improve the common good. They then return to the bar, which demons have infiltrated, and escape with the humans to Janet's void, leaving Earth.
The experiment was invalidated, so there is no real way to determine whether it was a success or a failure. Although the humans' original attempts to become good people failed, perhaps they would have become good people later in their lives.
Due to Michael's tampering, the humans probably would have become better, if not great, people, had Michael not attempted to keep the experiment going.
In the end, the experiment was irrelevant, because Michael realized that there was a much bigger problem with the afterlife: the point system. His entire experiment was based upon the idea that the point system was fair, so it ultimately told him nothing about how the Afterlife could be improved. However, Michael used the primary idea of this experiment in his third experiment, which posited that humans were hindered from improving on Earth due to life's complexities; he created a new Neighborhood in The Medium Place to test four new humans and see if they could improve.