There isn't a conclusion nowadays on how intelligent the App Store search engine algorithm is when understanding that singular and plural forms mean the same thing, thus combining search results for both forms. I never trusted the App Store enough to ignore the decision between singular and plurals, or go with one of them. I've always searched singular and plural keywords and most of the times I got significantly different results. To prove my point better, I chose two apps to which keywords I had access to, as a starting point, and went on investigating them. In this presentation I hope to better explain how does the singular and plural keywords App Store connection works.

1. Singular and Plural
Keywords Put to the Test
Does it matter if you use singular or plurals for
keywords in the iOS App Store?

2. The App Store is a black box.

3. Each update, the App Store algorithm gets
more complex and intelligent.

4. But how smart is it now?

5. When working on Keyword Optimization
(KWO), it's common to face the singular-plural
form dilemma.

6. Having "car,cars" in your Keywords field
seems like a waste of space

7. But to delete one of them, you have to trust
that the App Store will actually consider your
app eligible to both singular and plural forms.

8. There isn't a consensus yet on how
intelligent the search engine algorithm is.

9. If you search some words in singular and
plural on the App Store, you will probably get
very different results.

10. That's why WordData decided to investigate.

11. Singular and Plural Keywords
THE QUESTIONS

12. 1 Does the app appear on search
results for both singular and plural
forms even when using just one of
them?
In other words, does singular trigger plural
(and vise versa)?

13. 2 Does the search results position
for one form match the other?
If not, how much is the difference in the search
results positions?

14. 3 Is it better to use singular or plural
forms?

15. Singular and Plural Keywords
THE TEST

16. We chose two high-performing apps to serve
as a basis for our research.

17. Keywords are from the App Name and
Keywords field only.

18. Data was gathered directly from iPhone 5's
running iOS 8.

19. Although faster and easier to use, the
desktop iTunes search has a different
ranking algorithm.

20. One of them had the US App Store, the other
the French one.

21. We matched each keyword with their
respective singular or plural forms, even
when they didn't exist.

22. Why?
It would help us understand if the App Store
just combines everything with “-s” and marks
them as plural, or if it's more intelligent than
that.

23. We used keyphrases in all searches, by
combining a very relevant word with the
actual tested keyword

24. Singular and Plural Keywords
THE ANSWERS

25. 1 Does the app appear on search results for
both singular and plural forms even when
using just one of them?

26. 1 Does the app appear on search results for
both singular and plural forms even when
using just one of them?
It depends.

27. Here's the results for the United States store
—served by the English localization.

28. Connection Between Singular and
Plural Forms – United States
For App A,
92%
of Keywords
triggered their
respective plurals
For App B,
38%
of Keywords
triggered their
respective plurals

29. In the French store, results were low for both
apps.

30. Connection Between Singular and
Plural Forms – France
For App A,
24%
of Keywords
triggered their
respective plurals
For App B,
30%
of Keywords
triggered their
respective plurals

31. Could the connection App A had in the US
App Store be an anomaly?

32. We were using plurals that don't exist, such
as the and thes, so we checked if word
creation was the cause of that.

33. All the singular forms from this research
exist as words, so we checked the plurals.

34. Relation Between Singular and Plural
Forms - English
True – the word exists, is indeed a plural
form
No Relation – the word exists, but no relation
to the singular form, i.e. different meaning
Fake – the word does not exist

35. Relation Between Singular and Plural
Forms - English
App A
True - 71%
No Relation - 12%
Fake - 17%
App B
True - 46%
No Relation - 12%
Fake – 42%

36. Relation Between Singular and Plural
Forms - French
App A
True - 78%
No Relation - 0%
Fake - 22%
App B
True - 75%
No Relation - 6%
Fake - 19%

37. Comparing App A's English localization with
App B's, there could be a positive correlation
between made-up words and lack of
connection.

38. Maybe the App Store recognizes indeed
when a word exists before connecting
singular and plurals.

39. As for the French localization, even with a
good number of real plurals, the connection
didn’t pass 30%.

40. What we know for sure is that the French
algorithm is not as advanced as the English
localization one.

41. 1 Does singular trigger plural (and vice versa)?
This is more related to the word
and language itself than the form,
it seems.
We couldn’t find anything that
pointed to a preference for singular
or plural words.

42. 2Does the search results position for one form
match the other?
Most of the times, no.

43. The English localization for App A had the
highest number of matches, while App B in
France had the worst.

44. Search Results Position Matches Between
Singular and Plural Forms (when both forms
are not present in the keyword pool).

45. Relation Between Singular and Plural
Forms - English
Match – exactly the same position
Chosen – chosen form has better search
results positions
Opposite– opposite form has better search
results positions

46. Position Matches Between Singular
and Plural Forms – United States
when both forms are not present in the keyword pool
App A
Match - 37.5%
Chosen - 50%
Opposite - 12.5%
App B
Match - 4%
Chosen - 83%
Opposite - 12.5%

47. Position Matches Between Singular
and Plural Forms – France
when both forms are not present in the keyword pool
App A
Match - 11%
Chosen - 89%
Opposite - 0%
App B
Match - 0%
Chosen - 100%
Opposite - 0%

48. What can we take away from this?

49. Choose the form you want to rank higher on.

50. Even if you appear on both forms, the one
you actually have in your keyword pool will
receive a bonus thanks to being an exact
match.

51. If relevance between singular and plural is
the same (watch out for words like new and
news), go for the one with less competition.

52. For languages other than English, if both
keywords have similar stats, I recommend
using both.

53. For languages other than English, if both
keywords have similar stats, I recommend
using both.

54. 2 How much is the difference in the search
results positions between the chosen form
and the opposite form?
We’ve calculated it, but it’s
inconclusive.

55. Why?
Because it’s dependent on several other
aspects, e.g., how well-combined the search
results are, the keyword difficulty, and how
high up in the search results the app is
positioned

56. 3 Is it better to use singular or plural forms?
Just pretend that singulars and
plurals don't exist, consider
everything.

57. For the English localization, it’s pretty safe to
go with singular forms…

58. … though you could lose some positions on
the plurals. In our test, it was between 1-6
positions when the app was inside the top
20.

59. For languages other than English, don't
count on the algorithm to combine the
forms.

60. Using the French test as example, It couldn’t
match most of the simplest plurals (made
with –s or –x).

61. The ideal scenario, for maximum
optimization, is always analyzing singular
and plural forms as different words—
regardless of language.

62. Singular and Plural Keywords
CONCLUSION

63. There’s ample room for algorithm
improvement in languages other than
English.

64. For this language though, if the word has real
singular and plural forms, the match is
intelligent enough.

65. That said, we still recommend ignoring the
match.

66. Even if with a bigger research I got numbers
that pointed out most of the keywords were
correctly combined, there’s the exact match
bonus.

67. This alone is enough to study the metrics for
singular and plural.

68. Should you use both forms then?
When using both, you take space away for
different keywords.

69. Compare the stats for the keyphrases you’d
be losing with the ones you’d be ranking with
both forms.

70. As always, look for:
Relevance;
Competition;
Traffic.
In that order.

71. The final answer regarding singular and
plurals?
Think like you’re comparing different
keywords, as usual.

72. THANK YOU!
Evaldo Rossi
Founder at WordData
Rossi@WordData.com
@EvaldoRossi
WordData.com