Changes with metrics

Different versions of Project Analyzer may report different values for the same metric. There can be changes with the definition of a metric. There can also be improvements in the code analysis, which produces more accurate metrics as a by-product.

If you intend to compare projects, or different versions of the same project, you should analyze them with the same version of Project Analyzer and with the same settings. Comparing metrics stored with different Project Analyzer versions can lead to the wrong conclusions about the quality or development done on the code.

This page is about changes to metrics: the way they are defined and calculated. This page lists no new metrics, only old ones that were changed.

Metrics change history

Tip: If you wish to measure the amount of change that affects your old metrics data, do a simple test: Analyze the same project with the current Project Analyzer and your previous version. Compare the values you get. The metrics with large changes should not be used for comparison.

Change list

The following is a list of the known changes to metrics in Project Analyzer v8.x and v9.x. Other changes can exist, especially under some specific circumstances.

Metrics changes in Project Analyzer v10.1
Metric Vers. Description Projects affected Effect
VARS, VARSloc v10.1 Block-level local variables (several local variables with the same name) are now included in the variable count metrics. VB.NET Increase
CONSTS v10.1 Block-level local constants (several local constants with the same name) are now counted in CONSTS. Rarely seen in real code. VB.NET Slight increase
Metrics changes in Project Analyzer v9.0
Metric Vers. Description Projects affected Effect
TCC for classes v9.0 TCC for a class now counts complexity of Custom Event accessors too. Project Analyzer v8.x did not include them. This only affects classes with Custom Events. The project-level TCC is not affected by the change. VB.NET 2005 Increase
System complexity
v9.0 Project Analyzer v9.0 improved the analysis of late-bound calls. In projects using late binding, system complexity related metrics may differ significantly from values stored with previous Project Analyzer versions. All with late binding None to significant
-21% to +19%
Dead code metrics
v9.0 Due to more accurate analysis, dead code metrics may have changed. All Slight change
VARS, VARSloc v9.0 Implicit arrays, those declared via ReDim without a preceding Dim, are now included in the variable count metrics. VB 3.0 - 6.0 Slight increase
Metrics changes in Project Analyzer v8.1
Metric Vers. Description Projects affected Effect
DCALLT, maxDCALLT v8.1 DCALLT has been fixed for recursive call trees. What is more, it is now being approximated for complex recursive call trees. All Increase (fix)
Decrease (approximation)
AHF, MHF v8.1 A bug caused MHF and AHF to be miscalculated by Project Analyzer v8.0. It has been fixed. The bug didn't affect all projects, just some. If MHF or AHF changed a lot, this indicates the fix affected your program. VB.NET None to significant
Metrics changes in Project Analyzer v8.0
Metric Vers. Description Projects affected Effect
VARS => VARSloc v8.0 VARSloc (local variables) was previous called VARS. It has been renamed to avoid confusion with other variable counts. All
CDENS => CALLDENS v8.0 CALLDENS (call density) was previously called CDENS. It has been renamed for clarity. All
CALLS, CALLDENS v8.0 Setting the function return value (myfunc = retval) is no longer counted in CALLS or CALLDENS. All Significant decrease
-15% to -62%
LLINES, LLOC, LLOC% v8.0 Attribute lines (VB 4.0 - 6.0) are no longer counted into LLOC or LLINES (nor into STMT or STMTd either, for that matter). They can thus appear to have decreased a little. For the same reason, LLOC% may also have decreased a little.

Slightly decreased LLOC or LLINES is not deleted code!

VB 4.0 - 6.0 Slight decrease
LLOC'%, LLOW%, MCOMM% v8.0 If the amount of code decreases as mentioned above (LLOC), the amount of commentation and whitespace increases accordingly. VB 4.0 - 6.0 Slight increase
Statement counts
v8.0 The statement count metrics may have changed slightly due to subtle changes in the counting routines. All Slight changes
dVARS, DEAD v8.0 The number of dead variables now always includes variables that are read only or written only. This increases both dVARS and DEAD. All Increase
LENP v8.0 LENP Length of procedure names doesn't count the length of Operator names as Operator names are pre-defined. This is a definition update for VB.NET 2005, not a real change. VB.NET 2005 None
Object-oriented metric changes
MOOD metrics v8.0 MOOD metrics take both Property Set and Get accessors into account. In Project Analyzer v7, each VB.NET property was taken only once because Get/Set always have the same scope in VB.NET 2002 and 2003. Now that VB.NET 2005 allows different scopes for Get/Set, we consider each accessor. For the sake of conformance, we do the same for 2002 and as well. The change gives more weight to properties. VB.NET 2002 and 2003 Small
AIF, MIF v8.0 MIF and AIF were reported too high by Project Analyzer v7. Therefore, old MIF and AIF values are no longer displayed. VB.NET Breaking change; significant decrease
PF v8.0

Classes with explicit Inherits System.Object are considered for PF. Project Analyzer v7 left them out accidentally.

Protected Overrides Sub Finalize is not counted as it is derived from System.Object, not your own classes.

VB.NET with Sub Finalize Decrease if lots of Finalize
RFC, RFC', CBO, MPC v8.0 Improved analysis can have found new calls (such as calls to constructors), which increases RFC, RFC', CBO and MPC. Projects with classes Increase
RFC 0%..+3% RFC' 0%..+49% CBO 0%..+26% MPC 0%..+17%
LCOM2, LCOM3 v8.0 Constructors and destructors are no longer counted as methods for LCOM2 and LCOM3, as they frequently access many or all variables in a class. Projects with classes Increase
WMCi, VARSi v8.0 Bug fix: WMCi and VARSi were erroneously zero for projects with just 1 class. Projects with 1 class Increase
Changes with complexity, call tree and fan-in/fan-out metrics
Cyclomatic complexity

CC, CC2, CC3, TCC: Each Catch branch counts as one decision (previously none) and Catch..When counts as two (previously none). An unconditional Do..Loop does not add complexity (previously added 1).

CC2 now counts Boolean operators in Catch..When (previously not).

An additional change affects class-level TCC: A bug caused too low TCC for abstract classes with MustOverride procedures. The magnitude of that bug was equal to the number of MustOverride procedures.


More changes with VB.NET

Slight changes
DCOND, DLOOP v8.0 Fix: End While now correctly terminates a While loop for DCOND and DLOOP. The bug caused too high values for DCOND and DLOOP. Maximum bug effect: +1 for each End While. VB.NET with While..End While Small decrease
System complexity

The values of DC, SYSC and RSYSC have changed compared to values reported by earlier versions.

  • DC (IOvars) does not count the function return value if it is not set. Slight decrease
  • DC (IOvars) counts the return value of Property Get. Increase
  • Changes in SFOUT, caused by improved analysis, affect SC and DC. SC increase, DC decrease
All Noticeable change SC -3%..22%
DC -14%..+19%
SYSC -6%..+21%
RSYSC -11%..+21%

The call tree metrics can have increased due to a) improved analysis that finds more calls and b) due to corrections in the way these metrics are calculated. The increases vary from none to relatively high values. Large increases are possible for individual functions.

All Large increases possible maxDCALLT 0..+44%
DCALLT 0..+70%
LLOCt 0..+34%
SFIN, SFOUT for files v8.0 Late-bound calls now add to file-level SFIN and SFOUT. In Project Analyzer v7, late-bound calls were not counted. To get back old behavior, disable late-bound analysis in the General options dialog.

Improved analysis can also have found new calls, which further increases SFIN and SFOUT.

All Increase
0% to +76%
SFIN, SFOUT for procedures v8.0 Improved analysis can have found new calls, which increases SFIN and SFOUT, especially for calls to constructors and default members. All Increase
0% to +15%
Information flow
v8.0 The information flow metrics now report different values compared to earlier Project Analyzer versions. The changes are due to improvements in determining "in" and "out" parameters for IFIN and IFOUT. All Noticeable changes IFIN -2%..+7%
IFOUT 0..+11%
IFIO 0..+10%
IC1 -2%..+16%

The change percentages in the above table are estimated based on min..max changes found in analysis of 17 VB6 projects with Project Analyzer v7.1.01 and v8.0.01, and 20 VB6 projects with Project Analyzer v8.0.01 and v9.0.01. The changes are project-level averages (min..max). Changes with individual files, classes, procedures or even projects can be larger.

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