Best practice for splitting columns with multiple, comma separated values

Hi dphillips , great question.  Can I suggest that you Unpivot questions into rows, then split:

From:

To:

Here is the example code:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUUrUUUjSUUgGsip0FCp1FKqALEMdBSOlWJ1oJSdCCpwJKXDBqyAWAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Student = _t, #"Question 1" = _t, #"Question 2" = _t, #"Question 3" = _t]),
    #"Unpivoted Columns" = Table.UnpivotOtherColumns(Source, {"Student"}, "Attribute", "Value"),
    #"Split Column by Delimiter" = Table.ExpandListColumn(Table.TransformColumns(#"Unpivoted Columns", {{"Value", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv), let itemType = (type nullable text) meta [Serialized.Text = true] in type {itemType}}}), "Value"),
    #"Trimmed Text" = Table.TransformColumns(#"Split Column by Delimiter",{{"Value", Text.Trim, type text}})
in
    #"Trimmed Text"

I would add a dimension tables for Student and Questions.  You can use CALCULATE( exp , KEEPFILTERS( Question = 1 ) ) in your DAX functions.