I am trying to develop a program where the end state will be this program finding all instances of similar text within cells from multiple sheets and grouping it together. This question is going to deal specifically with the sub process I am trying to make dealing with the comparison portion. I created the following code which is simply a test to see how my comparison could work. It compares two cells right next to each other and goes letter by letter and spits out a similarity score. The code is below

Option Explicit
Sub ComparisonTest()
    Dim arr         As Variant
    Dim columncount As Integer
    Dim rowcount As Long
    Sheets(1).Select
    arr = ActiveSheet.Range("A1").CurrentRegion
    columncount = UBound(arr, 2)
    rowcount = UBound(arr, 1)
    Dim N           As Long
    Dim Letter      As Long
    Dim test1_string        As Variant
    Dim test2_string        As Variant
    Dim Test1_Comp As String
    Dim Test2_Comp As String
    Dim similarity As Integer
    Dim lettercount As Integer
    Dim lettercount2 As Integer
    'initialize count
    'construct loop from top to bottom and left to right
    For N = 1 To rowcount
    lettercount = Len(Cells(N, 1).Value)
    lettercount2 = Len(Cells(N, 2).Value)
        If lettercount2 > lettercount Then
        lettercount = lettercount2
        Else
        End If
    test1_string = CStr(Cells(N, 1))
    test2_string = CStr(Cells(N, 2))
        For Letter = 1 To Len(Cells(N, 1).Value)
            Test1_Comp = Mid(test1_string, Letter, 1)
            Test2_Comp = Mid(test2_string, Letter, 1)
                If Test1_Comp = Test2_Comp Then
                    similarity = similarity + 1
                Else
                End If
        Next Letter
            If similarity > (lettercount * 0.9) Then
                Cells(N, 3).Value = (similarity / lettercount)
                Cells(N, 3).Interior.Color = vbGreen
            Else
                Cells(N, 3).Value = (similarity / lettercount)
                Cells(N, 3).Interior.Color = vbRed
            End If
            similarity = 0
    Next N
End Sub
The problem with this code is the results are not what I am wanting. For example if I have entries "This is a test string" compared to "Ths is a text string" due to my macro comparing value by value a mistake in the beginning makes the similarity score very low when in actuality the only error is a missing "i" Does anyone have suggestions for this code to compare word by word instead of value by value? I use the word value here because there will be instances where the "text" will include numbers such as 90% for example.