In the final weeks of 2018, travelers around the world found a few surprises when claiming their Adventure Sync weekly distance rewards! To discover what had changed, the Silph Research Group immediately sprang into action. Here are the preliminary results based on over 500 datapoints gathered thus far:
You are now guaranteed to receive 500 Stardust for achieving 25km and an additional 1,000 Stardust for achieving 50km. Previously, Stardust was only one possible bundle amongst the other random rewards.
Poké Ball rewards remain unchanged. You receive a Poké Ball bundle of increasing quality (but decreasing quantity) for each weekly distance goal you manage to complete.
You still typically receive one additional random bundle for achieving 25km and another random bundle if you reach the 50km distance goal.
The chances of receiving an egg appear to have increased. As long as you have both egg slots and Pokémon storage slots available, you are very likely to receive a random egg bundle instead of one of the other options.
Eggs acquired through weekly distance rewards now contain a more diverse selection of hatchable Pokémon.
It is possible to receive no additional random bundles at all. In the vast majority of cases, this seems to occur if you do not have egg slots open or your Pokémon storage is full. Hopefully, this is a bug which will be fixed in the near future!
Due to the unexpected nature of the update, this data was collected via an internal Research Group survey instead of our usual methodologies, and as such, there is a possibility some bias was introduced in the process. However, this bias would likely be relatively small for these kinds of results.
Egg drop chances
Combining our results for the 25km and 50km tiers, 354 out of 379 open egg slots that were eligible for eggs were filled (over 93%), with a similar rate on both reward tiers. Most of the researchers who had spaces open but did not receive eggs had recently hatched a Pokémon, although that didn’t block reward eggs for all researchers. It is also important to remember that you cannot receive eggs if your Pokémon storage is full, even if you have free egg slots.
Of the researchers who had no egg slots available, approximately half of all random bundles were not awarded as expected based on our current understanding of the mechanics. These missing bundles occurred at a similar rate in both reward tiers.
Reward egg contents
In addition to looking at reward distribution as a whole, the Research Group has also investigated the contents of reward eggs. Prior to this set of changes, the egg pool was very small with 50km rewards offering Riolu and Shinx from 10km eggs and Buneary from 5km eggs. Turtwig, Piplup and Chimchar previously populated 5km eggs received from the 25km reward tier.
The recent update expanded the egg pool as follows:
| 50km tier | |||
|---|---|---|---|
| 10 km |
     |
5 km |
 |
| 25km tier | |||
| 5 km |
      |
||
Some may be disappointed about the seemingly lower chances of hatching that elusive Riolu, now that there are more species in the egg pool. However, the chances of getting an egg from weekly distance rewards have increased overall. A sneak peek from the results of our Adventure Sync Egg Task Force shows that Riolu is still hatching from roughly a third of the reported 10km reward eggs, while Trapinch and Ralts are significantly rarer in comparison. However, data is still being collected so proper rarity tiers will have to wait for later.
Speculation (Danger Zone!)
On the missing bundles
It has previously been speculated that the missing bundles are a direct result of the weekly distance reward system trying and failing to award an egg to a trainer that has no egg slot available. This was based on one key piece of evidence: that missing bundles occur more frequently when you do not have an egg slot available. However, we do not think this is the case. We believe instead that the bug is caused by Adventure Sync attempting to re-award the same Stardust bundles. There are two key pieces of evidence to support our case.
Firstly, from a probability perspective, if the bug was caused by a failure to award an egg, we would expect that over 90% of the bundles would have failed to be awarded to trainers without any egg slots available, as this was the egg drop rate when egg slots were available. However, our data indicates the probability of a missing bundle is in the neighborhood of 50%.
Secondly, there are several well-documented cases of trainers missing a bundle despite having the requisite egg slots. This should not be possible in the alternate case.
We propose that when rewards were buffed, Stardust became a guaranteed reward but was not removed from the possible random reward bundles. Hypothetically, these weights could be something like 95% : 2.5% : 1.25% : 1.25% for Eggs : Stardust : Rare Candy : Silver Pinaps. The net result of these weightings is that the missing bundle is awarded in about 50% of cases when there is no egg slots to fill, and in 2.5% of the cases where an egg slot is open. These probabilities are within the ranges we see in our data.
Keeping a single egg slot open
One question that has frequently been raised in the Silph Road community is the possibility of leaving a single egg slot open to receive rewards after reaching the 50km mark. Does the resulting egg come from the 25km reward pool, or the 50km reward pool? In our dataset, there appears to be a bias towards receiving an egg from the 50km reward pool (see table above for species) when you only have a single egg slot available (Chi-squared p-value = 0.00003). This is based on a small sample size of only 50 entries, so further investigation is necessary.
Parting Words
As this was a very quick research project, more investigation is needed into these new mechanics, and especially concerning the missing bundles and the conditions under which travelers might not receive an egg even when they have an egg slot open. This knowledge could add a new dimension to the weekly race to ascertain if you have the best possible chances to receive the rewards you most wish for, although it’s possible we won’t have to concern ourselves about the missing bundles for long if they are indeed the result of a bug. In either case, the Research Group will continue to keep an eye on the Adventure Sync weekly distance rewards and we’ll let you know if and when we have more exciting news to share about the subject. In the meantime, let’s keep walking and we’ll see you on the road!
