Calibration (The Process): Calibration is a set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument (or measuring system), and the corresponding values realized by standards.

Key Steps in Calibration:

• Comparison: Comparing the Unit Under Test (UUT) reading against a known Standard (reference).
• Documentation: Recording the "As Found" data to determine the instrument's performance before any changes.
• Uncertainty: Determining the measurement uncertainty associated with the readings.

Calibration vs. Adjustment:

1. Calibration: Is strictly a measurement and reporting process (establishing relationship). It does NOT involve changing the instrument's performance.
2. Adjustment: Is the act of physically or electronically bringing the instrument's output into conformity with the standard. This is only done *after* calibration if the 'As Found' data shows it is out of tolerance.

Traceability: is the property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty.

The Standards Hierarchy (The Traceability Chain):

1. Primary Standards (National/International): Maintained by organizations like NIST (USA) or BIPM, these are the highest level of accuracy, often derived from fundamental physical constants.
2. Secondary Standards (Reference Standards): Used in accredited laboratories to calibrate working standards. They are periodically calibrated against Primary Standards.
3. Working Standards (Laboratory Standards): Used by technicians daily to calibrate field instruments (UUTs). These are the most frequently used and calibrated.
4. Unit Under Test (UUT) / Field Instrument: The instrument being calibrated, which draws its traceability directly from the Working Standard.

• Accuracy: How close a measurement is to the true value (the closeness of agreement between a measured value and a true value). It is often quantified by the Measurement Uncertainty.
• Precision (Repeatability): How close multiple measurements are to each other (the closeness of agreement between indications obtained by replicate measurements). A precise instrument may still be inaccurate if it consistently reads high or low.
• Resolution: The smallest change in the measured quantity that causes a perceptible change in the corresponding indication of the measuring instrument. A high-resolution instrument may display 0.001 units, but it may not be accurate.

Measurement Uncertainty: is a non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used. In simple terms, it's the doubt that exists about the result of any measurement.

Importance of Uncertainty:

1. Compliance: Calibration is useless without knowing the uncertainty. It determines the probability that the actual value falls within the stated range.
2. Risk Management: By calculating uncertainty, organizations can assess the risk of making an incorrect decision (e.g., accepting a product that is out of specification, or rejecting one that is in).
3. Test Uncertainty Ratio (TUR): This is the ratio of the permissible tolerance of the UUT to the uncertainty of the standard. A minimum TUR of 4:1 (or ideally 10:1) is generally required, meaning the Standard is at least 4 times more accurate than the tolerance allowed for the UUT.

These two data sets form the core of a calibration record, providing a full audit trail of the instrument's status.

• As Found Data:

  This is the performance data recorded *before* any adjustments or repairs are made. It answers the crucial question: "Was the instrument measuring correctly before the service?" It is vital for determining if any products manufactured or processes controlled since the last calibration are affected by the drift.

• As Left Data:

  This is the performance data recorded *after* any necessary adjustments, repairs, and calibration are complete. It confirms that the instrument is now performing within the required tolerance and establishes the starting point for the next calibration interval.

A typical 5-point calibration checks 0%, 25%, 50%, 75%, and 100% of the measurement span, both upscale (increasing pressure) and downscale (decreasing pressure), to check for linearity and hysteresis.

Procedure Outline:

1. Setup: Isolate the transmitter, vent residual pressure, and connect the reference standard (e.g., Dead Weight Tester or precision pressure calibrator) to the transmitter's pressure port. Connect a DMM or process meter to the output signal (e.g., 4-20,mA).
2. Upscale Check: Apply pressure corresponding to 0%, 25%, 50%, 75%, and 100% of the range. At each point, record the reference pressure and the output current (mA).
3. Downscale Check (Hysteresis): Immediately decrease the pressure, hitting the same 100% to 0% points, and record the output current again. Hysteresis is the maximum difference between the upscale and downscale readings at the same test point.
4. Adjustment (If Necessary): If the 'As Found' data is outside tolerance, adjust the Zero (at 0%) and Span (at 100%) of the transmitter and then perform a full 'As Left' calibration run.

CJC: Thermocouples measure temperature based on the voltage produced by the junction between two dissimilar metals (the Seebeck effect). However, they also produce a voltage at the connection point between the TC and the measuring instrument (the "cold junction").

Explanation and Necessity:

• The Problem: The measured voltage is proportional to the difference in temperature between the hot junction (process temperature) and the cold junction (ambient temperature at the connection block).
• The Solution: CJC is a method (usually using a precision RTD or thermistor) to accurately measure the temperature of the cold junction. This compensation value is added to the measured TC voltage to calculate the true temperature at the hot junction.
• Field Calibration: During field calibration, the technician must ensure the calibrator is correctly compensating for the cold junction, often by using a dedicated calibrator that simulates the TC signal and includes an internal CJC sensor.

Calibration intervals are dynamic and should be based on risk and performance, not fixed schedules. The interval should be reviewed using data.

Key Factors for Interval Determination:

1. Stability History: Reviewing 'As Found' data from previous calibrations. If an instrument is consistently found far from its tolerance limit (low drift), the interval can potentially be extended. If it is consistently found "Out of Tolerance" (OOT), the interval must be shortened.
2. Manufacturer's Recommendation: This provides a good starting point, typically 12 months, but is often conservative.
3. Usage Severity: Instruments in harsh environments (vibration, extreme temperatures) or used frequently will likely require shorter intervals than instruments in stable environments used sparingly.
4. Criticality: Instruments controlling critical safety parameters or product quality attributes require more stringent and possibly shorter intervals.

Hysteresis: is the difference between the upscale (increasing input) reading and the downscale (decreasing input) reading at any single test point (excluding the end points) during a full calibration cycle.

Identification and Causes:

• Identification: It is identified by performing a full calibration cycle that includes stepping both up and down across the entire range. If the instrument's reading at 50% input is 12.0,mA when going up, but 12.5,mA when coming down, the hysteresis is 0.5,mA.
• Causes: Hysteresis is often caused by mechanical friction, backlash in gear systems (common in mechanical gauges), or magnetic effects in certain electrical systems. It indicates that the instrument's mechanical or sensing element is not perfectly elastic or responsive.

The Calibration Certificate is the primary evidence of traceability and performance. Without it, the instrument's measurements are scientifically invalid and non-compliant with standards like ISO 9001 and ISO/IEC 17025.

Mandatory Contents:

1. Identification: Unique certificate number, date of calibration, and date of issue.
2. UUT Details: Manufacturer, model number, serial number, and a clear description of the item calibrated.
3. Standard Details: Identification of the reference standards used, including their certificate numbers and due dates.
4. Results: The 'As Found' and 'As Left' data, clearly stating the results and whether the instrument was found to be "In Tolerance" or "Out of Tolerance".
5. Traceability & Uncertainty: A statement of traceability to national/international standards (e.g., NIST), and the calculated measurement uncertainty for the calibration.
6. Environmental Conditions: Temperature, humidity, and other relevant conditions during calibration.

• Linear Calibration: Assumes a straight-line relationship between the input and output (e.g., 4-20,mA output proportional to 0-100 PSI input). It usually only requires adjustment at the minimum (Zero) and maximum (Span) points.
• Non-linear Calibration: Used when the relationship is curved or complex (e.g., pH sensors, square root output from DP flow meters). This requires multi-point calibration (typically geq 5 points) across the range to confirm and adjust the instrument's characteristic curve.

1. Zero Shift (Bias): The error is constant across the entire range (e.g., the instrument reads 2 mA high at every test point). This is corrected by adjusting the Zero.
2. Span Shift (Gain Error): The error increases or decreases proportionally across the range (e.g., accurate at 0%, but 1 mA high at 100%). This is corrected by adjusting the Span.
3. Non-linearity: The deviation from the ideal straight-line relationship is non-proportional, typically worse in the mid-range points (25%, 50%, 75%). This requires sensor replacement or digital linearization adjustments.

A calibration standard must meet rigorous criteria to ensure it can accurately support the calibration of a UUT.

• Traceability: Must have an unbroken chain of calibrations back to a National Metrology Institute (NMI).
• Accuracy/TUR: Must be significantly more accurate than the UUT, typically with a Test Uncertainty Ratio (TUR) of at least 4:1.
• Validity: Must have a current, valid calibration certificate and be within its calibration interval.
• Range: Must cover the full operational range of the UUT being calibrated.

ISO/IEC 17025 is the international standard for the competence of testing and calibration laboratories. It goes beyond the Quality Management requirements of ISO 9001.

1. Technical Competence: Assesses the technical capability of the lab, including staff expertise, validity of methods, and suitability of equipment.
2. Valid Results: Requires labs to use traceable standards and calculate measurement uncertainty, ensuring the reported results are reliable.
3. Acceptance: Accreditation to 17025 provides international recognition, meaning test and calibration results are more readily accepted globally without further testing.

RTD: Measures temperature by correlating the resistance of the sensing element (usually Platinum, Pt100) with temperature.

Advantages over TC:

• Superior Accuracy & Stability: RTDs are inherently more linear and stable over time, resulting in higher accuracy and less drift than TCs.
• No Cold Junction Compensation (CJC) Issues: RTDs do not rely on the Seebeck effect and therefore do not require the complex and error-prone CJC required for TCs.
• Interchangeability: RTD elements of the same type (e.g., Pt100) are generally more consistent and interchangeable without recalibration than TCs.

• Bench Calibration (Component): The instrument is removed from the process and calibrated in a controlled laboratory environment. This provides the lowest uncertainty but only tests the component itself.
• Loop Calibration (System): The instrument remains connected to the control loop (transmitter, wiring, PLC/DCS input card). This checks the total error of the entire measurement path but typically has higher uncertainty due to field conditions and component tolerances.

Total Loop Error: The combined error of all components in a control loop (sensor, transmitter, wiring, and receiver/display). It's calculated by taking the square root of the sum of the squares of the individual component errors (Root Sum Square - RSS method).

Importance:

• System Performance: It provides the most realistic assessment of the overall system accuracy, as the weakest link often determines the loop performance.
• Maintenance Strategy: Helps identify which component contributes the most error, guiding replacement or repair efforts (e.g., if the display is $5\times$ less accurate than the transmitter, replacing the display is the priority).

• Static Calibration: The input quantity is held constant at several points (e.g., 25%, 50%) while the output is measured. This checks steady-state accuracy, linearity, and hysteresis.
• Dynamic Calibration: Involves varying the input quantity over time (transient response) to check the instrument's speed, time constant, and response to changing conditions. This is critical for instruments used in fast-acting control systems.

1. Multifunction Calibrator (Process Calibrator): A single, portable device capable of measuring and simulating multiple signals (Voltage, Current (mA), Resistance, RTD, TC). Essential for loop checking and transmitter calibration.
2. Dead Weight Tester (DWT): A highly accurate primary/secondary standard used for pressure calibration. It uses precise masses placed on a piston to generate exact, traceable pressure.
3. HART Communicator: A device used to digitally communicate with smart field instruments (HART protocol) to perform remote configuration, zero trimming, and diagnostics.

Dead Band: The range through which an input signal can be varied without causing an observable change in the output signal.

Why it is Undesirable:

• Loss of Control: It causes a control loop to cycle or oscillate because the controller must generate a large error signal before the final control element (like a valve) starts to move.
• Process Variability: It leads to slow or delayed responses, increasing variability in the process and potentially causing product quality issues.

SIL Rating: A measure of the safety system's reliability (probability of failure on demand). SIL 1 is the lowest, SIL 4 is the highest.

Impact on Calibration:

• Shorter Intervals: Instruments in higher SIL-rated loops (SIL 2, 3) often require much shorter calibration intervals to minimize the probability of failure.
• Documentation Rigor: The documentation and validation processes for calibration must be significantly more rigorous and auditable.
• Accuracy Demands: Standards used to calibrate SIL instruments must have extremely high accuracy (low uncertainty) to maintain the required integrity level.

pH calibration is typically a two- or three-point process using buffer solutions of known pH values.

1. Slope (Span) Calibration: Calibrate the meter using two different buffer solutions (e.g., pH 4 and pH 7). The difference in voltage readings between these two buffers determines the electrode's slope, which is critical for accuracy.
2. Zero (Asymmetry) Adjustment: Calibrate with a neutral buffer (pH 7) to adjust the offset of the meter. An ideal electrode should produce 0 mV at pH 7
3. Verification: Use a third buffer solution (e.g., pH 10) that was not used for adjustment to verify the linearity and 'As Left' performance.
4. Maintenance: Ensure the pH electrode is properly cleaned and stored in the correct storage solution between uses.

Flow calibration is challenging as it often requires traceable standards that can generate a flow rate, often necessitating bench calibration.

• DP/Mag Meter: Can often be 'dry' calibrated in the field by simulating the 4-20, mA output signal or verifying the input signals (e.g., for Mag flow, checking the coil resistance).
• Coriolis/Turbine: True calibration requires a traceable flow laboratory (a flow rig) that uses methods like mass collection or master meters to verify the meter factor. Field calibration is usually limited to verifying electronics/output only.
• Importance of K-Factor: The meter's K-Factor (pulses per unit volume) is the critical parameter determined during the initial traceable flow calibration and is entered into the transmitter.

Guard Banding: The practice of establishing tighter, internal calibration limits (the guard band) than the instrument's official Maximum Permissible Error (MPE) or tolerance limits.

Purpose:

• Mitigating Risk: The guard band compensates for the measurement uncertainty of the standard used. If a measurement falls just outside the MPE, it could still be acceptable within the uncertainty limits. Guard banding reduces the risk of accepting a non-conforming product.
• Preventing OOT: Instruments adjusted to the inner guard band have a greater chance of staying 'In Tolerance' until their next scheduled calibration.

1. Isolate & Notify: Immediately tag the instrument as OOT and notify the process/quality control team to prevent further use.
2. Determine Impact: A Quality/Metrology team investigates the instrument's 'As Found' drift history, determines when the OOT condition likely started, and assesses the impact on all products, batches, or processes controlled by the instrument since the last successful calibration.
3. Remedial Action: Adjust, repair, or replace the instrument. Once repaired/adjusted, perform a full 'As Left' calibration to restore compliance.
4. Document: Record all steps, findings, corrective actions, and impact assessments in the quality management system.

• Thermal Equilibrium: For temperature, the sensor (UUT) and the reference probe must achieve the same temperature within the calibration source (dry block or bath). Failure to wait can lead to thermal gradient errors.
• Pressure Decay: For pressure, high-pressure systems require time for pressure to settle and for any adiabatic heating effects to dissipate, especially in pneumatic systems.
• Process Stability: Waiting for stabilization ensures that the measurement being taken is a true representation of the steady-state value, minimizing dynamic errors.

The MDS serves as the single source of truth for an instrument's identity and maintenance requirements.

1. Identification: Tag number, serial number, location, manufacturer, and model.
2. Technical Specs: Range, units, output signal (e.g., 4-20,mA), accuracy specifications, and operating environment limits.
3. Metrology Data: Last calibration date, next due date, required Test Uncertainty Ratio (TUR), and calibration procedure number.
4. Criticality: Classification of the instrument (e.g., critical for safety, quality, or process control).

• Simulation Method: Since wet calibration (filling the tank) is often impractical, DP transmitters are calibrated by simulating the differential pressure corresponding to the tank's level range (e.g., 0% and 100% level pressure).
• Dry Leg vs. Wet Leg: Calibration must account for the density of the fluid and whether the reference leg is dry (atmospheric pressure) or wet (filled with a known fluid).
• Zero Suppression/Elevation: If the transmitter is mounted below (suppression) or above (elevation) the 0% level tap, this must be calculated into the calibration setup to ensure the 4 mA output corresponds to the true zero level.

An accredited lab is formally recognized by an accreditation body (e.g., A2LA, UKAS, NABL) as being technically competent to carry out specific calibrations.

• Compliance: The lab meets the strict requirements of ISO/IEC 17025 (or equivalent national standards).
• Scope of Accreditation: Accreditation is not universal; it is limited to a "Scope" which details the specific measurements the lab is authorized to perform, the lowest uncertainty they can achieve (CMC), and the range of those measurements.
• Trust: It ensures the highest level of quality and traceability, providing confidence in the results for legal, regulatory, or commerce purposes.

Environmental conditions can significantly influence the performance of both the UUT and the standard.

1. Temperature: Can cause dimensional changes (affects mechanical devices) or shift electronic components. Calibrations are ideally performed in temperature-controlled labs (20 DegC \pm 2 Deg C).
2. Humidity: Can affect electrical insulation, cause corrosion, or introduce errors in hygroscopic standards.
3. Vibration: Can cause unstable readings, especially in mass or force measurements. Labs must be physically isolated from vibration sources.
4. Management: Labs continuously monitor conditions, record them on the certificate, and apply correction factors if necessary, based on the instrument's known environmental coefficients.

This addresses the critical issue of lead wire resistance in resistance thermometry.

• Problem with 2-Wire: In a 2-wire connection, the measuring instrument measures the resistance of the sensing element AND the resistance of the lead wires, introducing a significant positive error.
• 4-Wire Solution: A 4-wire configuration uses two wires to carry the current and two separate wires to measure the voltage drop across the sensor element only (Kelvin sensing). Because the measuring device has high input impedance, virtually no current flows through the measuring wires, eliminating the effect of lead wire resistance entirely, resulting in much higher accuracy.

• Zero Adjustment (Offset): This adjusts the output signal at the Low Range Value (LRV), ensuring the output is 4 mA (or 0% output) when the input is at its lowest specified point. This corrects for *Zero Shift*.
• Span Adjustment (Gain): This adjusts the output signal at the High Range Value (HRV), ensuring the output is 20 mA (or 100% output) when the input is at its highest specified point. This corrects for *Span Shift*.
• Interdependence: These adjustments are interdependent. Changing the span often affects the zero, so both must be checked iteratively.

R_0 (Resistance at Zero Degrees Celsius): is the resistance of the RTD element when the temperature is exactly 0 Deg C.

• Base Reference: It is the base reference point for all temperature calculations made by the instrument based on the Callendar-Van Dusen equation.
• Sensor Integrity: Checking the R_0 value (either physically at 0 Deg C or by extrapolation) during calibration verifies the health and accuracy of the RTD element itself, separate from lead wire errors.

Valve positioner calibration ensures the valve stem position accurately tracks the control signal (e.g., 4-20 mA).

1. Input Range Check: Input 4 mA (or 0%) and confirm the valve stem is at 0% position. Input 20 mA (or 100%) and confirm the stem is at 100% position.
2. Linearity Check: Apply 5 or more test points (e.g., 8 mA, 12 mA) to verify the relationship between current input and stem position is linear or follows the prescribed characteristic (e.g., quick-opening, equal percentage).
3. Hysteresis/Dead Band Check: Test both upscale and downscale to identify friction or backlash issues that cause non-responsive movement.

• Drift: The gradual change in a measurement instrument's output over time that is unrelated to a change in the input quantity or operating conditions.
• Impact: Drift causes the instrument to become OOT between scheduled calibrations. If historical 'As Found' data shows significant drift, the calibration interval must be shortened to ensure the instrument remains within tolerance during its service life.

• CCP: A point in a process (e.g., HACCP in food safety) where failure to meet a specific parameter (e.g., pasteurization temperature) could result in a dangerous or unusable product.
• Special Care: Instruments controlling CCPs must have the highest level of accuracy, the shortest calibration intervals, and robust documentation, often mandated by regulatory bodies like the FDA. The TUR requirement is often much stricter.

TDR: The ratio of the maximum flow rate to the minimum flow rate over which the meter maintains its specified accuracy. (e.g., 10:1 means it's accurate from 10% to 100% flow).

• Accuracy Check: Calibration test points must cover the entire turndown range, especially at the lower end where accuracy typically degrades.
• Selection Factor: A meter with a high TDR (e.g., 100:1 for Coriolis) is preferred when the process flow varies widely, making the meter easier to calibrate across its operating spectrum.

• Pneumatic Calibration: Uses a gas (usually air or nitrogen) as the pressure medium. It is suitable for low-to-medium pressures (typically up to 1000 PSI). It is safer and cleaner for general process instruments.
• Hydraulic Calibration: Uses a non-compressible liquid (oil or water) as the pressure medium. It is necessary for high-pressure calibrations (up to 60,000 PSI) where gas compression is impractical or dangerous. It tends to be more precise at high pressure but messier.

• NDT Definition: Inspection techniques (e.g., Ultrasonic, Radiographic, Magnetic Particle) used to evaluate the properties of a material, component, or system without causing damage.
• Instrument Integrity: NDT is used to check the structural integrity of instrument components (like pressure vessel walls, thermowells, and primary flow elements) that interface with the process, ensuring they won't fail during operation, which complements the functional verification of calibration.

The VMP is a high-level document that describes the overall strategy and organization for process and equipment validation within a facility.

• Scope Definition: Identifies which instruments, systems, and processes require formal validation (IQ/OQ/PQ) and GxP compliance.
• Governance: Specifies roles, responsibilities, and documentation standards for all validation activities, including the qualification of calibration procedures and standards.
• Schedule: Provides a timeline for validation and re-validation, ensuring continuous compliance.

• Definition: A secure, computer-generated, time-stamped record that independently records the date and time of operator entries and actions that create, modify, or delete electronic records (e.g., calibration data).
• Compliance: Essential for regulatory compliance (e.g., FDA 21 CFR Part 11) as it proves who did what, when, and why, ensuring data integrity and non-repudiation.

1. Evidence of Traceability: The calibration certificate, which is documentation, is the only proof that the measurements are traceable to national standards.
2. Auditability: Regulatory and quality audits require complete, chronological records (As Found/As Left data, OOT reports) to prove that quality systems are functioning correctly.
3. Interval Management: Historical data is used to analyze drift, determine stability, and justify changes to calibration intervals.

This effect is significant when calibrating pressure instruments, especially manometers or high-accuracy standards.

• Gravity Variation: The local acceleration due to gravity changes with elevation. High-accuracy calibration often requires compensating for the difference between the local gravity value and the standard gravity value (9.80665 m/s2).
• Pressure Head: When using fluid-based standards (like DWT), the pressure head created by the height difference between the DWT's piston and the UUT's sensing element must be calculated and corrected.

• SRM Definition: A material or substance, often certified by an organization like NIST, where one or more property values are established sufficiently well to be used for calibration or quality control.
• Usage: They are crucial in analytical chemistry and material science. Examples include certified gas mixtures for gas chromatographs or certified buffer solutions for pH meters. They provide immediate traceability for property values.

1. Primary Standards: The highest level, maintained by NMIs (NIST, NPL). They are derived from fundamental constants (e.g., the speed of light for length). Used only to calibrate secondary standards.
2. Secondary Standards (Reference): Used in accredited labs. They are calibrated directly against primary standards. Used only to calibrate working standards.
3. Working Standards: Used daily by technicians to calibrate field instruments (UUTs). They are calibrated against secondary standards. They are the least accurate but most numerous in the chain.

• Correction: Auto-zero is a function in many digital instruments that measures and compensates for the internal electronic offset (zero drift) of the instrument's circuit board.
• Timing: It should typically be performed before a high-accuracy calibration and during periods when no input signal is applied. It ensures the 4 mA (or 0 output) is purely due to process signal and not electronic noise.

• System Integration: Load cells are highly sensitive to side loading, binding, piping constraints, and mounting stresses. Bench calibration only checks the cell itself, ignoring the physical system effects.
• In-Situ Accuracy: Calibrating a tank or silo weighing system in-place (in-situ) ensures the system's full measurement uncertainty accounts for all mechanical influences, providing the true 'As Used' accuracy.

• MPE: The maximum allowable error that an instrument can have and still be considered "In Tolerance" and fit for its intended use.
• Acceptance Criteria: The calibration result (reading vs. standard) is compared to the MPE. If the measurement error is less than the MPE, the instrument is compliant. The MPE often comes from the manufacturer's specification or a company's internal process requirement (Process Tolerances).

• Analog (Trim Pot): Involves physically turning potentiometers (trim pots) or mechanical linkages to adjust the output (4mA and 20 mA).
• Smart (Digital/HART): Calibration is typically done digitally using a handheld communicator or software. A technician performs a "sensor trim" (adjusting the primary variable at the sensor level) and a "D/A trim" (adjusting the output signal DAC). These digital trims are far more precise and stable.

The Quality Manual is the top-tier document that outlines the company's commitment to quality and compliance with standards (e.g., ISO 9001, ISO/IEC 17025).

• Policy Statement: Defines the Metrology/Calibration policy, including objectives for quality, traceability, and customer satisfaction.
• Reference Map: Acts as a map, referencing the procedures (SOPs) for specific tasks (e.g., handling OOT, calibration methodology, record retention).
• Audits: Used by auditors to understand the organizational structure and commitment to quality assurance before reviewing detailed work instructions.