<s>
Predictive	B-General_Concept
mean	I-General_Concept
matching	I-General_Concept
(	O
PMM	O
)	O
is	O
a	O
widely	O
used	O
statistical	O
imputation	B-General_Concept
method	I-General_Concept
for	O
missing	O
values	O
,	O
first	O
proposed	O
by	O
Donald	O
B	O
.	O
Rubin	O
in	O
1986	O
and	O
R	O
.	O
J	O
.	O
</s>
<s>
It	O
aims	O
to	O
reduce	O
the	O
bias	O
introduced	O
in	O
a	O
dataset	O
through	O
imputation	B-General_Concept
,	O
by	O
drawing	O
real	O
values	O
sampled	O
from	O
the	O
data	O
.	O
</s>
<s>
Compared	O
to	O
other	O
imputation	B-General_Concept
methods	O
,	O
it	O
usually	O
imputes	O
less	O
implausible	O
values	O
(	O
e.g.	O
</s>
<s>
negative	O
incomes	O
)	O
and	O
takes	O
heteroscedastic	B-General_Concept
data	I-General_Concept
into	O
account	O
more	O
appropriately	O
.	O
</s>
