Question Trying to better understand waterfalls management

Hi aboudiab! Thanks for trying Unity Mediation, and your interest in Unity Levelplay! Happy to answer your questions above.

1 - Requests indicates how many times an ad request was made to that specific line item. In a traditional waterfall like you have, the ad request will go one by one from highest to lowest target eCPM until the request is filled. It's not unusual for line items at the top of the waterfall to receive the most requests, and then dwindle as you go down the list.

Sometimes when you make a request to an ad network, based on the parameters set such as any floors or targets, there may not be an ad available at that time. Fill rate indicates what percentage of time an ad is available when one is requested, for that line item. As you guessed, impressions (8 for this line item) indicates how many times the available ad was actually shown to a player.

Think of it like a funnel with drop offs at each step, eg ad is requested --> ad is received from the network (fill) --> ad is loaded --> ad is successfully shown to the player (impression)

2 - Low impression means not many players are being shown the ad. If the requests and fill rate are very high but impressions are low, there might be an issue where the ad itself is having problems loading for the player. Alternatively if impressions are low across all line items for a waterfall, consider when you are loading an ad (usually when the game initializes) vs when this specific ad unit is called to be shown (eg, if it's buried deeper in the game session, it's possible players are just not coming across this surfacing point).

3 - Ad requests move one by one through the waterfall until an ad is returned. The order that the ad request moves through the waterfall is based on the eCPM target that you set for each line item. Setting a line item higher in the waterfall means it will have a higher chance of being requested for an ad. If this line has a high CPM, it should improve your earnings. However make sure to double check whether you have any floors set for that line item with the network.

Low fill rate of higher priced line items in and of itself is not a bad thing. For example, if your first line item is for a target of $1000, the chances of it filling at $1000 is quite low, so fill rate will understandably be low. You may want to adjust your target eCPMs (make sure the floors match!) or consider the target eCPM intervals between your line items to capture the highest CPM and revenue for an ad request.

If you don't want to managed traditional line items (because it can be quite tedious!), consider using bidding instead, if that's an option from the network.

4 - For line items with 0 requests, it means the waterfall usually fills somewhere higher up before it gets to those lines. For smaller waterfalls there's not a lot of harm, but if you are worried about increased latency, you may reduce the number of line items to focus on the more "successful" ones.

We also have this best practices guide for managing your waterfall.

Hope this helps!