Previously, I have blogged on using the principle of flow to build ranking ladders and scale them to match the skill level of the superusers in your community. Because these blog articles are the foundation for this blog, I strongly recommend reading them first if you haven't. They can be found here:
In a benchmark study I conducted last year, we found that healthy and vibrant communities that have many superusers generally have a large number of ranks. In fact, the benchmark list of top communities has an average of 31 non-role-based ranks (ranks that are achievable through participation). If we include role-based ranks (that were assigned), the average is 59. Among these top communities, the number of ranks goes as high as 134 ranks. But does this apply to your community? The important questions are: How many ranks does YOUR community need, and how many is enough?
The answer is that you need as many ranks as necessary to keep your most active superuser engaged. The exact number will depend on how prolific your most active superuser is. I will illustrate this with the calculation on Lithosphere again. Last time we've designed an optimal ranking ladder for Lithosphere. The post requirement for each rank are: 3 posts, 9, 18, 30, 45, 63, 84, 108, 135, 165, 198, 234, 273, 315, 360, 408, 459, 513, 570, 630, 693, 759, 828, and finally 900 posts at the 24th rank. We've also calculated the post rate for all users who have been in the community for more than 2 weeks and sorted them. If you look at the previous blog, you will see that ScottD is the most active superuser on Lithosphere (he also happens to be our community admin, but let's ignore that for now). He has posted 451 messages in total and his post rate is 1.16 posts/day. If ScottD wasn't our admin, he would be on the 16th rank now. So the proposed rank ladder with 24 levels is definitely enough for now.
A natural question is when will this rank ladder become insufficient? If ScottD posts 450 more messages, his post count will exceed 900. After that, his contribution will no longer be rewarded by this ranking ladder. Soon after, he may become bored with the community. How long would that take? Since we have ScottD's post rate, 450 more posts would take him about (450 post)÷(1.16 posts/day)=388 days. So in a little more than a year, it will be time to adjust this ranking ladder. What do we need to do a year from now to keep ScottD engaged in his personal flow state? Add more ranks! But how should we set the rank criteria? Remember, if it's too easy, ScottD will be bored, and if too hard, he might become frustrated and leave.
Note that the gap between the 23rd and 24th rung of the ranking ladder is (900-828)=72 posts. For typical Lithosphere superusers with post rate of 0.851 posts/day, this will take them about (72 posts)÷(0.851 posts/day)=85 days, which is almost 3 months. Even for ScottD, the most prolific superusers on Lithosphere, it will take him about (72 posts)÷(1.16 posts/day)=62 days, which is about 2 month. This means the gaps between the top rungs of our existing ranking ladder is already challenging for our superusers. So after the 24 linearly incremental ranks that are designed to engaged the superusers of Lithosphere, it is a good time to switch to the arithmetic progression (a.k.a linear progression), which has a constant growth rate. The logical choice is to continue the rung spacing between the top ranks of the existing ranking ladder. How many ranks we add depends on how soon we want to adjust the ranking ladder again. If we want to challenge ScottD with the appropriate difficulty for 1 more year, we will need to add at least 6 ranks, starting with the 25th rank requiring 972 posts, and then spaced evenly every 72 posts thereafter.
Why wouldn't we just add 60 more ranks and be good for the next 10 years? You can, but I certainly would not recommend that because ScottD's capability may change. Perhaps another more prolific superuser will come along, or maybe some other superusers will surpass ScottD. So we may need to change the spacing of the linear progression again the following year. In general, it is a good idea to re-compute the post rate of your top superusers yearly (or semi annually) and adapt the post criteria to keep the "flow" with your superusers. Alternatively, if you have a superuser MVP program, you can also switch your top contributors to an assigned-rank system to build a more personal relationship with your superusers.
Next time we will add some mysteries and surprises to spice up your ranking ladder and explore what happens after we switched the ranking criteria over to the arithmetic progressions. Come and follow my update at mich8elwu. May the flow be with your superusers!