Here, I will go through each of the three games and describe its structure both as a chain of links and as a graphical depiction of its linearity. Progression is based on quest completion, not on time. Some quests take longer than others, but that is irrelevant for a study of linearity. I will assume you are familiar with the games I am analyzing due to their popularity. If you are not, the title headings are links to that game's Wikipedia entry. Clicking each thumbnail will take you to a full size image.

I only did full chains for the PE chain and the Fighters' Guild, House Hlaalu and Imperial Cult NPE chains, as they are fine exemplars of the other chains of their type (guild, house and other). NPE quests were counted by their relation to a faction and secondly whether they gained reputation with that faction. Looking at both figures, we see that Morrowind is replete with parallel quests, both in the PE and NPE chains. We also see that the “sandbox” or “non-linear” nature of Morrowind is far less clear than most would claim. There is a great selection of different NPE goals a player can fulfill, but each one is more or less a linear progression to the end. Even those that have significant choice in quest selection, such as House Redoran and the Fighters' Guild, the selection is meaningless because all quests must be completed to gain sufficient reputation to continue through to the chain's end, of which there is only one (The Fighters' Guild is unique in that is has two ways to seize control, but the difference is superficial, as the result is the same either way).

In this way, Morrowind gives the illusion of substantive choice simply by allowing the player to satisfy quests in an order that he chooses, through judicious use of parallel quests. The only real choice the player has is which Guild and House to join, as each Guild is mutually exclusive with other Guilds and Houses are likewise with other Houses. This choice, however, significantly cuts down on the system's flexibility, because chains from which the player is barred are useless; they do nothing to add “openness” or nonlinearity to the game because they are not all available at the same time. This barrier is extremely important. Look at figure 2, the graphical depiction of linearity in Morrowind. Only one of the guild chains (the red ones) are accessible in any given play-through. Similarly, only one of the house chains (the blue ones) are available. Out of 10 NPE chains, only 5, half of the full total, are available on any given play-through.

Even with all those chains barred, however, Morrowind is still overwhelmingly an NPE-focused game. 18.7% of the game's quests are PE, which leaves 81.3% of the quests as NPE for a given playthrough (taking the “average” House and Guild chains). The highest total of parallel quests available in Morrowind is 17.

FFIX is a good example of the other extreme. If Morrowind is a field of shrubbery, Final Fantasy IX is a tall, barren tree. The player has little to no choice, substantive or otherwise, as to how the game progresses, merely follows a very long chain of PE quests with the (very) occasional NPE diversion, usually a sort of minigame or an internal motivation/external goal mission for better gear. Surprisingly, FFIX is just about exactly what consumers has it pegged as: a mildly interactive graphic novel. The disjointed quests are the Chocobo/Ozma line of quests, which become “available” early on but can only be satisfied at a much later time.

80% of the quests in FFIX are PE. 20% are NPE and the highest number of parallel quests a player has available at any time is 3.

Either through luck or design, Bioware's games have generally avoided characterization as either type of traditional RPG. Whether this is due to something intrinsic in the game itself, or due to Bioware's rather cult-like following is unclear. While we are describing games as shapes, KotOR is more of a short but full bush. The PE chain here is short, shorter even than the paucious chain in Morrowind. Bioware's games have often been criticized for having extremely short plots, even if those same plots are well-written and well-executed. There is only one nonlinear portion of KotOR, when the PE chain is spread out across Tatooine, Manaan and Kashyyk. For the PE quests, this is similar to the parallel structure in Morrowind. The NPE quests, however, are completely different.

Each major game area has a selection of NPE quests. Not only are these NPE quests almost all completely independent (the main reward for these quests is dark or light side points but unlike in Morrowind there is no actual light or dark side faction quest chain), they also are truly nonlinear in that it is possible to undertake and complete these NPE quests in any order starting from the moment you gain them, with some complications detailed below. Therefore, even while the NPE quests in Morrowind vastly outnumber those in KotOR, the player has greater flexibility, with a highest possible parallel quest total of 23. 26% of the game is PE quests, and 74% is comprised of NPE quests.