Waterfall best practices

To help you start exploring and setting up your monetization solutions by using the Unity Mediation platform, here are some best practices and tips to help you effectively monetize your app by using mediation.

Start with high eCPM targets and optimize downward

In traditional waterfalls, ad networks are chained together and called until demand is depleted before moving on to the next provider. With mediation and waterfall advancements, a more optimized approach is taken by using a performance-based ranking system. The order in which an ad network is prioritized is now based on the publisher’s target (floor) eCPM for each network. This ensures that the publisher shows the highest-performing ad to their users, and maximizes their yield.

Generally, you start with high eCPM targets and work down according to your app's unique breakdown. The following image is an example distribution of an optimized waterfall:

Ensure adherence to target eCPM

When checking performance metrics for a traditional waterfall setup, it is important to ensure that the ad network placement’s actual eCPM (the revenue earned per one thousand impressions) is either equal to or above the target eCPM (the eCPM that was set in the meditation tool). Checking this number ensures that the ad networks are adhering to the price floor that you have set up and is often a great indicator if there is an error in operational setup.

In this example, the ad manager opens the Unity Waterfall Management tool to evaluate the waterfall performance:

Looking at the data, they notice that the placement line item that has a target at $75 is delivering a lot of impressions but at $52.23. This alerts the ad manager that there is an error that is occurring in the delivery.

Checking the dashboard, they notice that there has been a typo and they accidentally set the line to $75 instead of $52.23. Updating the line to $75, the placement is now filling as expected.

Swap and update networks

Over time, individual network performance can start to trend downward, so you might consider switching them with networks that are moving up. This can happen for many reasons such as individual demand campaign strength across the networks or changes in advertiser spend by network, among others.

Downward trends can also be related to out-of-date network adapters in addition to general demand weakness, so checking network adapters is always a good first step before making network changes. For the best performance, we recommend that you stay on top of these opportunities.

Ensure standardized line syntax

You will likely end up creating multiple placements for each network. Accordingly, it is important that you create a standardized naming structure to simplify waterfall management. Instead of using CPM price floors or pricing names like Premium, High, or Mid, we recommend that you use the following naming convention for your line items to allow greater flexibility as you continue to optimize and test new pricing strategies.

  • Template:

    “Adnetwork_platform_placement-type_number/letter”

  • Example:

    Unity_iOS_Interstitial_01, Unity_And_Rewarded_02

Sandwich waterfall setup for new apps

For a new app, use genre benchmarking to determine the top of stack, high range eCPM for your waterfall to compare the performance of your app with other similar ones in a given ad network. This lets you understand the strengths and shortfalls of your app, giving you the needed context to improve your waterfall implementation, or on a longer-term basis, to improve your app.

If genre benchmarking is not available for your app, a standard three-placement setup per ad source is a good starting point to establish baseline eCPM performance. This setup is known as the “Sandwich Model”, or the High / Mid / Low eCPM pricing approach.

How it works

In the Sort by eCPM Target section of the Waterfall Line Item page, set a High, Mid, and Low eCPM price point for your default waterfall line items. The insights gathered from this initial setup can direct you where to focus on new line item prices.

  • High eCPM price points: Low impressions, high revenue

  • Mid eCPM price points: Good impressions, high revenue

  • Low eCPM price points: High impressions, mid revenue

We also recommended that you add a backup waterfall line item to ensure all impressions are filled in the Auto-eCPM section of the Waterfall Line Item page.

Fixed decremental waterfall setup

Determine maximum and minimum eCPM, then fulfill the range between the maximum and minimum eCPM by creating a range of fixed decremental line items for your default waterfall, dipping into the backfill waterfall when necessary. This is a standard approach to yield optimization that ensures ease of setup and maintenance, as well as providing solid coverage throughout the waterfall for all ad sources.

How it works

Start by selecting the maximum eCPM and minimum eCPM to accept for a line item and determining the range between these eCPMs. Then, create line items to each cover a fixed decrease to implement over a range. For example:

$10 decrements starting from $60, down to $30.

  • This would require the creation of four line items, each with an eCPM of $60, $50, $40, and $30, respectively.

$8 decrements starting from $40, down to the backfill line item.

  • This would require the creation of 6 line items, each with an eCPM of $40, $32, $24, $16, $8, and the Backfill for the respective ad source.

If you prefer to have more control over the prioritization of your ad sources for the fixed decremental setup, you can do so manually. Use cents in your eCPM to prioritize your ad sources in the order you want them to be.

For example:

Unity line item eCPM= $5.02, AdMob line item eCPM= $5.01, AdColony line item eCPM = $5.00

General recommendations

  • We recommend that you get at least a week's worth of data before you make any significant changes to your waterfall to get a more accurate idea of the effectiveness and performance of your line items.

  • Waterfall activity is heavily dependent on volume. To find what works for you and your app, try different combinations of ad formats, ad sources, and eCPM pricing strategies to see what generates the most revenue in your app.

  • We recommend that you avoid increasing the number of placements you have until you reach the threshold of at least 1,000 impressions per placement a day.