Lack (verb) / Lack of (noun) / Lacking in
Different formsAs a verb, lack takes a direct object: the paper lacks evidence. As a noun, use lack of evidence. Use lacking in when describing a deficiency in a quality or feature.
Lack (verb)
Use when
You mean not have enough of something; place the missing thing directly after the verb.
Example
“The proposal lacks supporting evidence.”
Lack of (noun)
Use when
You use lack as a noun to describe an absence or shortage.
Example
“The panel was concerned about the lack of supporting evidence.”
Lacking in
Use when
You describe something as deficient in a quality or feature.
Example
“The implementation plan is lacking in operational detail.”
Quick check
the proposal lacks of evidence, there is a lack evidence, the plan is lack of detail
Usage note
Lacking can also appear without in where the missing item follows directly, but lacks of is not the standard verb pattern.