Table 1 Feature set for the library adoption model

Commit features (C)

 C1

# libs added by user

 C2

# libs updated since last commit

 C3

—C1 \(\cap \) C2—

User features (U)

 U1

Size of productive vocab \(P_u\)

 U2

Size of receptive vocab \(R_u\)

 U3

Time since last commit

 U4

Intra-commit duration in last 10% of commits

 U5

# Repos committed

 U6

# Repos committed in last 10% of commits

 U7

% commits with added libs

 U8

% commits with added libs in last 10% of commits

User–Library pair features (P)

 P1

# times user has seen \(\ell \)

 P2

# times user has seen any library

 P3

P1/P2

 P4

# times user has seen \(\ell \) in last 10%

 P5

# times user has seen any library in last 10%

 P6

P4/P5

Library features (L)

 L1

# commits adding \(\ell \)

 L2

# users who have committed \(\ell \)

 L3

# repos containing \(\ell \)

 L4

Time since last commit of \(\ell \)

 L5

Avg time between last 10% of commits adding \(\ell \)

 L6

Avg time between last 10% of commits adding \(\ell \)

StackOverflow features (S)

 S1

# posts containing \(\ell \)

 S2

# views of posts containing \(\ell \)

 S3

# posts containing \(\ell \) created in last 30 days

 S4

# views of posts containing \(\ell \) created in last 30 days