SPREADSHEET VALIDATION 101: CREATE AND VALIDATE FDA-COMPLIANT MS EXCEL SPREADSHEETS

SPREADSHEET VALIDATION 101: CREATE AND VALIDATE FDA-COMPLIANT MS EXCEL SPREADSHEETS 1 R A U L S O T O, M S C, C Q E I V T A P R I L 2 0 1 5 P H I L A D E L P H I A

ABOUT THE AUTHOR 20+ years of experience in the medical devices, pharmaceutical, biotechnology, and consumer electronic industries MS Biotechnology, emphasis in Biomedical Engineering BS Mechanical Engineering ASQ Certified Quality Engineer (CQE) I have led validation / qualification efforts in multiple scenarios: High-speed, high-volume manufacturing and packaging equipment Laboratory : information systems and equipment / instruments Enterprise resource planning applications (i.e. SAP) IT network infrastructure Software applications Product improvements, material changes, vendor changes Contact information: Raul Soto rasove_21@yahoo.com 2

TABLE OF CONTENTS 1. REGULATORY PERSPECTIVE 2. SPREADSHEET VALIDATION 3. BUILDING A COMPLIANT SPREADSHEET 4. HANDS-ON EXERCISES

SCOPE SPREADSHEET Microsoft Excel file that may contain: mathematical calculations Statistical analysis Graphing Outside our scope: Macros or custom code Database lookups 4

PART 1: REGULATORY PERSPECTIVE R E G U L A T I O N S G O V E R N I N G S P R E A D S H E E T S 5

WHICH SPREADSHEETS NEED TO BE VALIDATED? If the spreadsheet supports any activity governed by applicable regulations, it should be validated 6

FDA 483S AND WARNING LETTERS Companies have been cited by FDA for not validating spreadsheets used for: In process analytical calculations Finished Product analytical calculations Tracking and trending quality metrics Databases / list 7

Pharmaceuticals (Eli Lilly): FDA 483

FDA WARNING LETTERS Pharmaceuticals (Cardinal Health): http://www.contractormisconduct.org/ass/contractors/18/cases/305/221/f da-warning-letter.pdf

FDA WARNING LETTERS Pharmaceuticals (Aarti Drug Limited): http://www.fda.gov/iceci/enforcementactions/warningletters/2013/ucm 369409.htm

FDA WARNING LETTERS Biologics (National Genetics Institute): http://www.fda.gov/iceci/enforcementactions/warningletters/2006/u cm075766.htm

FDA WARNING LETTERS Medical Devices (Aubrey Inc.): http://www.fda.gov/iceci/enforcementactions/warningletters/2011/ucm2 56498.htm 12

FDA WARNING LETTERS Medical Devices (B. Braun Medical Ltd): http://www.ofnisystems.com/media/g3667d.pdf

FDA WARNING LETTERS Medical Devices (Eldon Biologicals A/S): http://www.ofnisystems.com/resources/warning_letters/g4452d.pdf

FDA WARNING LETTERS Medical Devices (EP Medsystems): http://www.ofnisystems.com/media/g1483d.pdf

MEDICAL DEVICES 21 CFR 820.70(i): Automated processes When computers or automated data processing systems are used as part of production or the quality system, the manufacturer shall validate computer software for its intended use according to an established protocol. All software changes shall be validated before approval and issuance. These validation activities and results shall be documented. 16

MEDICAL DEVICES Let s take this apart: Applies to computer / data processing systems used for production or quality The manufacturer is responsible for validation Validation must be for the intended use(s) Must have an established protocol Changes must be validated before implemented Document all validation activities and results 17

MEDICAL DEVICES Section 6.0 Many other commercial software applications, such as word processors, spreadsheets, databases, and flowcharting software are used to implement the quality system. All of these applications are subject to the requirement for software validation, but the validation approach used for each application can vary widely. 18

MEDICAL DEVICES Section 6.1 Numerous commercial software applications may be used as part of the quality system (e.g., a spreadsheet or statistical package used for quality system calculations, a graphics package used for trend analysis, or a commercial database used for recording device history records or for complaint management). The extent of validation evidence needed for such software depends on the device manufacturer's documented intended use of that software. 19

PHARMACEUTICALS 21 CFR 211.165(e): Testing and Release for Distribution (e) The accuracy, sensitivity, specificity, and reproducibility of test methods employed by the firm shall be established and documented. Such validation and documentation may be accomplished in accordance with 211.194(a)(2). 20

BIOLOGICS 21 CFR 606.140: Laboratory Controls Laboratory control procedures shall include: (a) The establishment of scientifically sound and appropriate specifications, standards and test procedures to assure that blood and blood components are safe, pure, potent and effective. (b) Adequate provisions for monitoring the reliability, accuracy, precision and performance of laboratory test procedures and instruments. (c) Adequate identification and handling of all test samples so that they are accurately related to the specific unit of product being tested, or to its donor, or to the specific recipient, where applicable. 21

ISO 13485 DESIGN AND MANUFACTURE OF MEDICAL DEVICES Clause 7.5.2.1 The organization shall establish documented procedures for the validation of the application of computer software (and changes to such software and/or its application) for production and service provision that affect the ability of the product to conform to specified requirements. Such software applications shall be validated prior to initial use. 22

ISO 13485 : 2015 DESIGN AND MANUFACTURE OF MEDICAL DEVICES Will explicitly mandate: That software used as part of the quality system must be validated and subject to change control. That we must have procedures to govern this That validation must be documented and the documentation maintained. 23

FDA LAB MANUAL OF QUALITY PROCEDURES http://www.fda.gov/scienceresearch/fieldscience /LaboratoryManual/ucm174286.htm 24

25

4.5.3 VALIDATION OF SPREADSHEETS SUMMARY Lock all non-input cells Make spreadsheets read-only, with password protection Automatically reject data outside valid ranges Positive and negative testing: Test by entering expected and extreme values, and nonsensical data Keep record of all cell formulas Document changes made to the spreadsheet Change control with version numbers Periodic re-validation spreadsheets, including verification of cell formulas manual verification of spreadsheet calculations 26

FDA S INTERNAL GUIDELINES FOR SPREADSHEET DESIGN AND VALIDATION Spreadsheet Design and Validation for the Multi- User Application for the Chemistry Laboratory: Part I www.spreadsheetvalidation.com/pdf/lib_design_multi- User2A.pdf Spreadsheet Design, Verification and Validation, Use and Storage of Single-User Workbook Files in the US FFDA Laboratories: Part II www.spreadsheetvalidation.com/pdf/lib_part_ii_single- User.pdf 27

COMMON SPREADSHEET ISSUES FOUND BY FDA IN INDUSTRY Spreadsheet files not maintained, some deleted Rounding errors Formulas don't match (Excel vs source, Excel vs manual calculation) Conversion factors issues Spreadsheet doesn't show specs or limits Unclear documentation Units not labeled Weights described as volumes, areas as ratios Security and data integrity issues Cells not locked Regressions that inverted X and Y axis 28

PART 2: VALIDATING THE SPREADSHEET V A L I D A T I O N P L A N, E X E C U T I O N, R E P O R T I N G 29

VALIDATING YOUR SPREADSHEET Validation : Provide documented evidence that the spreadsheet does what it is intended to do, correctly, and consistently 30

TYPICAL VALIDATION ELEMENTS Validation Plan Requirements Specification Design Specification Traceability Matrix Testing Validation Report Procedures & Governance Templates You can use separate documents for each Development Installation Qualification OQ / PQ -or- System / User Acceptance -OR- A single Validation Protocol that includes ALL validation elements 31

GOVERNANCE Spreadsheet Validation Procedure Outlines HOW spreadsheets will be validated What document(s) need to be produced Roles and responsibilities, Authors and Approvers, etc. Templates (i.e. Spreadsheet template) Change Control Procedure May be a separate procedure, or part of the main Spreadsheets Validation Procedure Validated Spreadsheet Inventory Training 32

GENERAL INFORMATION Spreadsheet name Description and Purpose What the spreadsheet will be used for Process(es) supported Where it will be used References Analytical methods, SOPs, etc. 33

REQUIREMENTS Describes, with detail, WHAT you want the spreadsheet to do. Requirements should be numbered MS Excel version required Excel Add-Ins required, if any OS version in which it is developed For example: MS Windows 7 SP1, Mac OS X 10.10 Include OS service pack, if applicable 34

REQUIREMENTS Input cell and formula cell requirements Formatting (colors, font size and type, etc.) Data validation (field type, size, etc.) Descriptions for every formula, and source Page formatting Titles Headers Footers 35

REQUIREMENTS Charts and Graphs Title and Description of each Required labels for each axis Security requirements Password protection Output requirements Color printer, PDF-creating software Specific folder in a specific shared drive Automatic email to specific people 36

DESIGN SPECIFICATION Describes, with details, HOW the spreadsheet will comply with the Requirements Address all requirements, individually or by groups Describes the actual spreadsheet as written Shows actual EXCEL version of formulas Describes algorithms used, if any Describe conditional cell formatting used, if any Describe data validation used, if any Describe outputs produced (i.e. graphs) 38

TRACEABILITY MATRIX Traces every requirement to its corresponding design element, and to the test script(s) where the requirement is challenged and tested. 39

DEVELOPMENT TESTING & DRY RUNS Recommended! Typically not documented formally Dev Testing helps discover bugs and fix them while we re not yet in formal validation. Dry Runs help discover issues with the validation test scripts, and allows us to fix these before we move into formal document change control. 40

INSTALLATION QUALIFICATION (IQ) IQ includes Installation and Configuration State all prerequisites, ensure they are met prior to execution List all spreadsheet files that have to be installed List location and path where spreadsheet files will be installed Development environment does not have to be validated Test environment may need to be validated Production environment must be validated 41

OPERATIONAL QUALIFICATION (OQ) State all prerequisites, ensure they are met prior to execution Verify that all requirements documented in the Requirements section are met Ensure all outputs have the correct formatting Provide printouts of all formulas, input values used, output results. Positive v Negative testing!!! Security testing Performance testing Simulate output issues 42

OPERATIONAL QUALIFICATION (OQ) Ensure all non-input cells are locked Ensure conversion factors are correct Ensure spreadsheets are read-only, with password protection Ensure the spreadsheet automatically rejects data outside valid ranges Test for rounding errors Ensure Excel formulas match the source formula Ensure formula input / output cells are correct Compare formula results vs manual calculations Ensure units and spec limits are present and correct 43

OQ: POSITIVE VS NEGATIVE TESTING Positive testing : test and verify every single formula using values that should produce correct results Ensure the spreadsheet produces correct results for various input data sets i.e. at least two data sets Data set 1: known to result in a PASS decision Data set 2: known to result in a FAIL decision Include test cases with borderline data Verify spreadsheet results against results from manual calculations 44

OQ: POSITIVE VS NEGATIVE TESTING OQ Negative testing : Use incorrect inputs to ensure the spreadsheet is robust, able to handle them without crashing or producing false or incorrect outputs, and that it is not possible to bypass security 45

OQ: POSITIVE VS NEGATIVE TESTING Negative testing examples: Required data entry : ensure input fields cannot be left blank Field type test: ensure data entered is of the correct type (i.e. dates, alphanumeric, etc.) Enter alpha or special (@%^#) characters on a numeric field Enter a decimal number in an integer field Enter negative numbers in a positive numbers field Enter nonsensical inputs (i.e. ASCII CRTL codes) http://academic.evergreen.edu/projects/biophysics/technotes/program/ascii_ctr l.htm Field size test: ensure user can only enter the specified number of characters in a field 46

OQ: POSITIVE VS NEGATIVE TESTING Negative testing examples: Date bounds test: test upper and lower bounds for dates. Numeric bounds test: for example, if the number in a field should be between 10 and 50, the system should not accept numbers lower than 10, and higher than 50. Numeric limits test: make sure the spreadsheet doesn t crash or produce incorrect output when entering a number outside of Excel s limits: Excel 2013 limits: https://support.office.com/en-za/article/excel-specifications-and-limitsca36e2dc-1f09-4620-b726-67c00b05040f 47

OQ: POSITIVE VS NEGATIVE TESTING For a good discussion, with examples, of Positive vs Negative software testing, please refer to: http://www.softwaretestingcl ass.com/positive-andnegative-testing-in-softwaretesting/ 49

OQ SECURITY TESTING Security testing: Ensure it is not possible to: Unlock locked cells / worksheets Alter formulas, output results, output graphs /charts/ tables Add or remove worksheets 50

OQ PERFORMANCE TESTING Output issues : ensure the spreadsheet behaves as expected when you disconnect printer close the PDF-rendering application Performance : Multiple users simultaneously Open multiple instances of the spreadsheet at the same time Execute spreadsheet while various other applications are running 51

OPERATIONAL QUALIFICATION Formula Auditing Excel s Formula Auditing tools allows us to demonstrate that the inputs come from the expected cells 52

TEST EXECUTION Ensure test scripts are executed in the appropriate sequence. Document deviations when actual results do not match expected results Take screenshots and printouts as documented evidence 53

TEST EXECUTION Include all executed test scripts Include all screenshots, printed outputs, manual calculations Post-approvals 54

CHANGE CONTROL AFTER VALIDATION Update Validation documentation Additional or changed requirements Corresponding design elements changes Update Testing New or updated test scripts Test new functionality (i.e. new/updated formula) Regression testing: ensure areas not changed still work correctly Update traceability matrix Upon release, increase the Version number REMOVE ACCESS to the old version 55

VALIDATION: HOW MUCH IS TOO MUCH? Depends on the level of risk 56

PART 3: BUILDING THE SPREADSHEET D E S I G N A C O M P L I A N T S P R E A D S H E E T 57

CHANGE CONTROL Spreadsheets used for GxP processes should be subjected to formal version control and validation. The organization s change management system should be used to document whenever we: Create a new spreadsheet for regulated / validated uses Make changes to a validated spreadsheet Retire/decommission a validated spreadsheet Move a validated spreadsheet to a different version of Excel (i.e. from Excel 2007 to Excel 2010) from the one used in development and validation Move a validated spreadsheet to a different operating system (i.e. from Windows to Linux or MacOS) 58

CREATING THE SPREADSHEET The following information (at minimum) should be included on the main worksheet: Spreadsheet Name Version number Date of last modification Every printout should contain this information 59

CREATING THE SPREADSHEET Verify formulas against sources Use correct units of measurement Lock all non-input cells Disable column/row add/remove Unlock input cells Distinguish input, calculation (formula) vs output cells Cell background color Font : bold, italics, size, color Use conditional formatting on output cells Different cell background color and/or font color for results that pass vs results that fail 60

CREATING THE SPREADSHEET Add a field where the user will enter his/her name every time the spreadsheet is used. Use Page Setup to print the following information: Spreadsheet filename Correct date and time Page numbers and total pages Make the spreadsheet read-only 61

UNITS CONVERSION You can use the Excel CONVERT function to convert values from one unit to another in your formulas Click HELP in Excel for a list of all units included. 62

CHANGE HISTORY Each spreadsheet should have a Change History worksheet (a.k.a. Revision History) Every time the spreadsheet is updated, an entry should be made in this Change History: New version number Date of change Change control number Name of person(s) who made the change Itemized description of ALL changes made (with DETAILS) 63

SECURITY LAYERS Lock all cells except user input cells. HOME tab/ CELLS group/ Format / Protection Password-protect the worksheet Prepare / Encrypt document Install the validated spreadsheet in a protected folder on a networked shared drive Access to the folder should only be given to authorized personnel OR save the validated spreadsheet as a controlled document in your EDMS 64

IMPORTANT!!! Locking / unlocking cells Protect spreadsheets /worksheets Cell formatting: Data types Look and feel : Font, Colors Validation criteria definitions for input cells Define formulas Use of logical statements in formulas Use of Page Set-up 65

PART 4: WORKSHOP H A N D S - O N S P R E A D S H E E T W O R K S H O P 66

SPREADSHEET CREATION Once you create your spreadsheet 1. ID cell types, by color 2. Conditional formatting for displaying results 3. Data validation 4. Formula auditing Trace Precedents and Dependents Show and evaluate formulas Error checking Preventing formulas from being displayed 5. Set print headers and footers 67

SPREADSHEET SECURITY 6. Protect the Worksheet 7. Unprotect input cells 8. Protect the Workbook 9. Protect and SHARE the Workbook 10. Tracking Changes 68

1. ID CELL TYPES BY COLOR Input Cells: Output Cells: Yellow background, red text Lt Blue background, black text 69

2. CONDITIONAL FORMATTING Conditional formatting can be used to change the formatting of a cell (background color, text color, text properties, etc.) depending on its content, or on the content of another cell 70

2. CONDITIONAL FORMATTING You can apply multiple formatting rules to a single cell Use Manage Rules to keep track of the rules you are applying. 71

2. CONDITIONAL FORMATTING Example 1 Minimum spec value is 14, maximum is 17 We want cells to be: Lt Green fill and Dk Green text IF value is between min and max Lt Red fill and Dk Red text IF value is outside min and max 1. Home / Styles / Conditional Formatting/ Highlight Cell Rules/ Less Than => dialog box 2. Select cell where minimum value is listed, and desired formatting: 72

2. CONDITIONAL FORMATTING Example 1 (cont.) 3. Home / Styles / Conditional Formatting/ Highlight Cell Rules/ Greater Than => dialog box 4. Select cell where maximum value is listed, and desired formatting: 5. Home / Styles / Conditional Formatting/ Highlight Cell Rules/ Between => dialog box 6. Select cells where maximum and minimum values are listed, and desired formatting: 73

2. CONDITIONAL FORMATTING Example 2: Have a cell that shows PASS or FAIL depending on the value of another cell We want PASS: Lt Green fill and Dk Green text FAIL: Lt Red fill and Dk Red text 1. = IF ({cell} <= {min value}, FAIL, PASS ) 2. = IF ({cell} >= {max value}, FAIL, PASS ) 3. Home / Styles / Conditional Formatting/ Highlight Cell Rules/ Text that Contains => dialog box 4. Format Cells that contain: FAIL with Lt Red Fill with Dk Red Text 5. Format Cells that contain: PASS with Lt Green Fill with Dk Green Text 74

2. CONDITIONAL FORMATTING

3. DATA VALIDATION Use Excel s Data Validation tools to enforce limits in input fields. Examples: Integer input between 1 and 20 Alphanumeric field, from 1 to 16 characters Date or time Decimal number greater, lower or than a specific value; or between specific values Excel s Data Validation also allows you to: Display custom messages on input cells Display custom error messages when input is outside parameters 78

3. DATA VALIDATION TOOLS 79

3. DATA VALIDATION - SETTINGS Define the types of content that is allowed on the cell In this case the cell is restricted to positive decimal values 80

3. DATA VALIDATION INPUT MESSAGE Enter the Title and Input Message to be displayed when the mouse pointer hovers over the selected cell 81

3. DATA VALIDATION ERROR ALERT Enter the Error Alert message to be displayed if the data entered does not meet the restrictions. 82

3. DATA VALIDATION DATA TYPES Types of inputs: Any value Whole number Decimal List restrict input to items from a specified list List should be included in a protected column in the spreadsheet Date Time Text length Custom 83

3. DATA VALIDATION Example: restrict field to specific length 84

3. DATA VALIDATION Example: restrict possible values of a cell to those in drop-down list 85

3. DATA VALIDATION Example: prevent future dating Allow: Date Data: less than or equal to End Date: =INT(NOW()) If you want a date field to always auto-populate with the date the spreadsheet is executed, put =INT(NOW()) as the field value for that cell, and LOCK the cell (don t make it an input field). The user will not be able to modify that date. 86

3. DATA VALIDATION Custom: Example: ensure the entry in a column is a number 1. Select the column 2. select Data, Validation 3. Select the Settings tab 4. Select Custom from the Allow list 5. In the Formula field, enter =ISNUMBER(c1) 6. Click OK The ISNUMBER function returns TRUE if the cell contains a number 87

4. FORMULA AUDITING 4.1 Preventing formulas from being displayed 4.2 Trace Precedents and Dependents 4.3 Show and evaluate formulas 4.4 Error checking 88

4. FORMULA AUDITING 4.1 How to prevent your formulas from being displayed in the formula bar: 89

4. FORMULA AUDITING 4.1 How to prevent your formulas from being displayed in the formula bar: 1. Select formula cell 2. Right click and select Format Cell -OR- Home / Cells / Format / Format Cells 3. Protection: [ ] Locked [ ] Hidden 4. OK 5. Review / Changes / Protect Sheet => your formula will not be visible in the formula bar any longer 90

4. FORMULA AUDITING 4.2 How to trace Precedents and Dependents in your formulas: Precedents 1. Select formula cell 2. Formulas / Formula Auditing / Trace Precedents Excel will display arrows showing which cells your formula inputs come from Remove arrows deletes the arrows 91

4. FORMULA AUDITING 4.2 How to trace Precedents and Dependents in your formulas: Dependents 1. Select formula cell 2. Formulas / Formula Auditing / Trace Dependents Excel will display arrows showing which cells your formula sends outputs to Remove arrows deletes the arrows 92

4. FORMULA AUDITING 4.3 How to show and evaluate your formulas: Show your formulas: Formulas / Formula Auditing / Show Formulas 93

4. FORMULA AUDITING 94

4. FORMULA AUDITING 95

4. FORMULA AUDITING 4.3 How to show and evaluate your formulas: Evaluate your formulas: Select a formula cell Formulas / Formula Auditing / Evaluate Formula Keep pressing EVALUATE, and Excel will show you step-by-step, with all intermediate values, how it evaluates your formula and calculates a result 96

4. FORMULA AUDITING 97

4. FORMULA AUDITING 4.4 Formula Error Checking If there are errors in a formula (for example, entering a letter in a numerical input cell), Excel will show a #VALUE! error message Click on Formula / Formula Auditing / Error Checking 98

4. FORMULA AUDITING Error Checking will display the cause of the error (wrong data type in this example) 99

4. FORMULA AUDITING From this dialog box you can: Get HELP on the error type Show calculation steps (same as Evaluate Formula). You can see the step-by-step calculations Excel is performing to evaluate your formula Ignore Error: error checking will continue checking the rest of your spreadsheet and stop at all errors until it s done Edit in formula bar: Edit the formula cell 100

5. SET PRINT HEADERS & FOOTERS 1. File / Print / Page Setup / Header & Footer 2. Header: Custom header Left: Page & [Page] of & [Pages] Page x of xx Center: & [Tab] v1.0 Right: & [Date] & [Time] Date and time Worksheet name and version 3. Footer: Custom footer Left: & [Path] & [file] Path and filename Center: CONFIDENTIAL (use [A] icon to format text) Right: nothing add anything you want 4. OK 101

5. SET PRINT HEADERS & FOOTERS 102

5. SET PRINT HEADERS & FOOTERS 103

6. PROTECT YOUR WORKSHEET 1. Review tab / Changes group / Protect Sheet 2. Select locked cells 3. Select unlocked cells 4. Enter and re-enter worksheet password This password-protects your worksheet cells from any changes This also disables Column & Row Add / Remove BUT someone can still delete, add, and rename worksheets from the spreadsheet => Protect Workbook 104

6. PROTECT YOUR WORKSHEET 105

7. UNPROTECT INPUT CELLS 1. Review tab / Changes group / Unprotect Sheet 2. Enter password, press OK => worksheet is now unprotected 3. Click on Allow Users to Edit Ranges 4. When the Allow Users to Edit Ranges dialog box opens, click on NEW 5. When the New Range dialog box opens: Title: <any title you want> Refers to cells: range of input cell(s) Range Password: <don t pwd protect> OK, OK 6. Click on Protect Sheet : enter worksheet password, then OK 7. Now you can only change the values of the selected input cells 106

7. UNPROTECT INPUT CELLS 107

7. UNPROTECT INPUT CELLS 108

7. UNPROTECT INPUT CELLS 109

8. PROTECT YOUR WORKBOOK 1. Review tab / Changes group / Protect Workbook 2. [ ] Structure 3. [ ] Windows 4. Password: enter and re-enter worksheet password When the worksheet is protected, you can t add, remove, or rename worksheets in the MS Excel file To unprotect, click on Review / Changes / Protect Workbook and enter the password 110

8. PROTECT YOUR WORKBOOK 111

9. PROTECT AND SHARE WORKBOOK Once you are ready to publish your spreadsheet, use Protect and Share Workbook 1. Review / Changes / Protect and Share Workbook 2. [ ] Sharing with Track Change 3. Enter and re-enter worksheet password 4. SAVE the file The file will be saved, and will be ready for sharing Options to unprotect cells and worksheet will be Disabled 112

9. PROTECT AND SHARE WORKBOOK 113

10. TRACKING CHANGES 114

10. TRACKING CHANGES Excel s Track Changes functionality displays: Cells changed Date and time User who changed it Old and new value Helpful when you are editing a spreadsheet However it should not be used as a Part 11- compliant audit trail Can be turned on and off 115

10. TRACKING CHANGES When you turn on Track Changes, Excel will mark every cell you edit/change. If you hover the mouse pointer over the cell it will display the change information. Once you SAVE your worksheet, the change marks are removed 116

10. TRACKING CHANGES You can get a report that will show you all the changes made to the spreadsheet since the last save Review / Changes / Track Changes/ Highlight Changes 117

10. TRACKING CHANGES 118

10. TRACKING CHANGES If you want to review and Accept / Reject changes: Review / Changes / Track Changes/ Accept-Reject Changes 119

QUESTIONS 120

Thank You! 121