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The whole team fills in one uncertainty study.

In PureField LIMS, a measurement uncertainty study is a shared record for repeatability, intermediate precision, trueness, Nordtest or GUM. Invited analysts enter values; the server recalculates after each save. It moves through draft, data collection, evaluation and approval. An authorised person who neither entered values nor changed the study signs it, and the approved U is applied to the method.

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Analysts enter values; the LIMS works out uncertainty.

The quality manager invites the analysts and each one enters values in their own column. A stage strip says whose turn it is; the approved uncertainty is applied to the method.

The video opens the DON intermediate precision study on wheat flour as the analyst invited to the third operator column sees it; the stage strip says it is their turn. The analyst types three values into their own column, picks the instrument and saves; the group mean, s and the dot plot are recalculated. When the page refreshes, another analyst's last value appears in the grid; hovering it shows who entered it, when, the measurement date and the instrument. Once the study owner locks the data, the study moves to Evaluation: the strip says an approver who has neither changed the study nor entered values signs next, and the locked result shows RSD 1.653 % within the ≤ 15 % criterion, with the precision components as bars.

Each analyst, their own column
The study owner invites the analysts who will measure and gives each one a column; the invitee is notified. Each person enters values only in their own column, and only the person who entered a value corrects it, with a reason.
Who acts next
The stage strip shows where the study stands, from draft to approval, and whose turn it is. Statistics are recalculated on the server after every save, and an open page refreshes every 20 seconds while data are collected.
Independent, signed approval
The study owner locks the data. An authorised person who has neither changed the study nor entered values approves it with an e-signature, which covers the locked results and the evaluation.

Five steps from draft to method

A strip at the top of the study says which stage it is in and who acts next.

  1. Draft

    The person opening the study picks its type (repeatability, intermediate precision, trueness, Nordtest or GUM), the method, the parameter, the groups and the number of replicates, and may set an acceptance criterion. The study gets a number.

  2. Invitations

    Each column belongs to one person; one analyst may hold several columns. When data collection starts, every invitee gets a notification in the app and by email.

  3. Data collection

    Analysts enter their values, the measurement date and the instrument in their own columns and see everyone else's. Only the person who entered a saved value can correct it, with a reason.

  4. Evaluation

    The study's owner locks the data; the results are computed and stored on the server. An evaluation is written; if needed, the study goes back to data collection with a reason.

  5. Approval and method

    An authorised person who has not opened or changed the study, or entered values in it, signs it. An approved Nordtest or GUM result is applied to the method: U is rounded up to two significant digits and a new method version is created.

Calculation and record rules

The study is run under ISO/IEC 17025 §7.6 and §7.2.2.1. Every value is stored with who entered it, when, the measurement date and the instrument.

Outliers stay in
Cochran and Grubbs flag a value as straggler (5 %) or outlier (1 %). Every value stays in the calculation; flagged ones are examined in the evaluation.
Nordtest sources
u(Rw) comes from an entered value, at least 20 results of a control sample or an approved intermediate precision study. u(bias) comes from an entered value or an approved trueness study.
GUM budget
The model equation uses the method's formula language. Contributions are computed with the Kragten method and the effective degrees of freedom with Welch–Satterthwaite.
Recalculated at approval
Before approval the results are recalculated from the record and compared with the locked ones. The signature covers the inputs, a digest of the values, the results and the evaluation.
Earlier results keep their U
A new U applied to the method carries into results and reports entered from then on. Results entered earlier keep their own values.

Further reading

Frequently asked questions

Who enters values into an uncertainty study?

People invited to the study who hold the participate permission; by default lab managers, quality managers, technical approvers and analysts. Each column belongs to one person, who enters values there and sees the other columns. Correcting a saved value takes a reason, and the earlier value stays in the record history.

Who approves an uncertainty study?

An authorised person who took no step in the study. Someone other than whoever opened it, changed its design or inputs, started data collection, locked it, wrote the evaluation or entered values approves it with an e-signature. An approved study stays locked.

Can we use an uncertainty we already calculated in a spreadsheet?

Yes. In a Nordtest study, choose an entered value for u(Rw) and u(bias) and write its basis; your earlier result goes into the study that way. Repeatability, intermediate precision and trueness studies with new data are calculated in the app.

Free measurement uncertainty Excel template
How does an approved uncertainty reach results and reports?

On an approved Nordtest or GUM study, choose Apply to method, pick the level and write a reason for the change. U is rounded up to two significant digits (6.43 % → 6.5 %) and a new method version is created. Results and reports entered from then on carry the uncertainty with k = 2.

We'll show the demo with records close to your sample types.

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