Instruments

Every shipped instrument is a Questionnaire value. This page records what each one measures, how it is scored, and where it comes from.

Big Five Inventory-2 (bfi2)

Sixty items on a 1–5 agreement scale, completing the stem “I am someone who…”.

The BFI-2 is hierarchical: five domains, each resolved by three facets of four items. Both levels are declared as sibling subscales over the same item pool, so a single pass scores all twenty scales.

Domain	Facets
Openness	Intellectual Curiosity, Aesthetic Sensitivity, Creative Imagination
Conscientiousness	Organization, Productiveness, Responsibility
Extraversion	Sociability, Assertiveness, Energy Level
Agreeableness	Compassion, Respectfulness, Trust
Neuroticism	Anxiety, Depression, Emotional Volatility

Domains are emitted in OCEAN order, matching what the package has returned since 1.0.0 and what PersonalityLinMulT expects.

Note

The three Negative Emotionality facets score in the direction their names describe. Before 2.0 they were flipped unconditionally while the domain was not; see migration.

Soto, C. J., & John, O. P. (2017). The next Big Five Inventory (BFI-2): Developing and assessing a hierarchical model with 15 facets to enhance bandwidth, fidelity, and predictive power. Journal of Personality and Social Psychology, 113, 117–143.

Free for research purposes; see the authors’ terms.

BFI-2 Extra-Short Form (bfi2-xs)

Fifteen items on the same 1–5 agreement scale as the BFI-2, three per domain, one drawn from each of that domain’s facets. Retains roughly 80% of the full form’s domain-level reliability.

Domains only. With one item per facet the form cannot support facet scores, and the authors say so explicitly.

Every item is borrowed from the BFI-2 by reference rather than retyped, so a wording correction in the parent propagates automatically. Only the item-number mapping is local, and the reverse keys are derived from the parent rather than transcribed — polarity is a property of an item’s wording, so a borrowed item keeps the keying its source earned. A test checks the derived result against the published key regardless.

Note that the numbering is the short form’s own: item 1 of the BFI-2-XS is item 16 of the BFI-2.

Note

Short-form scores are not interchangeable with full-form scores item for item. The BFI-2 reverses exactly half of each twelve-item domain, so a constant response collapses to the midpoint; a three-item domain reverses one or two of three and cannot balance. Both forms agree at the scale midpoint, and diverge away from it.

Soto, C. J., & John, O. P. (2017). Short and extra-short forms of the Big Five Inventory-2: The BFI-2-S and BFI-2-XS. Journal of Research in Personality, 68, 69–81.

Big Five Inventory-10 (bfi10)

Ten items, two per domain, for settings under severe time pressure.

Unlike the BFI-2-XS, the BFI-10 is not a subset of the BFI-2. It descends from the older BFI-44, so its wording differs, its stem differs (“I see myself as someone who…” rather than “I am someone who…”), and its midpoint label differs (“Neither agree nor disagree” rather than “Neutral; no opinion”). Its items are therefore native and carry no source_number. Published labels are reproduced per form rather than harmonised across them.

Each domain deliberately pairs one positively and one negatively keyed item, so exactly five of the ten items are reversed and any uniform response cancels to the midpoint.

Domain	Items
Extraversion	1R, 6
Agreeableness	2, 7R
Conscientiousness	3R, 8
Neuroticism	4R, 9
Openness	5R, 10

Rammstedt, B., & John, O. P. (2007). Measuring personality in one minute or less: A 10-item short version of the Big Five Inventory in English and German. Journal of Research in Personality, 41, 203–212.

Positive and Negative Affect Schedule (panas)

Twenty mood adjectives rated 1–5 for intensity, ten forming Positive Affect and ten Negative Affect. The two scales are near-independent rather than opposite ends of one dimension — that is the instrument’s central claim, and it is why a negative adjective raises Negative Affect rather than lowering Positive Affect.

No item is reverse-keyed. Each adjective scores in the direction it is worded, making the PANAS the first shipped instrument with an empty reverse-key set.

Scale	Items
Positive Affect	1, 3, 5, 9, 10, 12, 14, 16, 17, 19
Negative Affect	2, 4, 6, 7, 8, 11, 13, 15, 18, 20

Two reported forms

Each scale appears twice in the output:

Subscale	Range	Use
Positive Affect / Negative Affect	[0, 1]	Consistent with every other instrument here
Positive Affect (sum) / Negative Affect (sum)	10–50	The form the literature is written in

The literature reports totals — Watson et al. give normative means of 33.3 for Positive Affect and 17.4 for Negative Affect — so the published totals are carried alongside the normalised means rather than left for the caller to reconstruct. A subscale declares this through SUM, and summed subscales are never rescaled, since normalising them would destroy the number their norms use.

Time frame

The stem reproduces the published default, “over the past week”. The window is the instrument’s one deliberate variable — Watson et al. validate everything from “right now” to “in general”, and the scale’s test–retest behaviour changes with it. A study using a different window should say so in its own materials.

Watson, D., Clark, L. A., & Tellegen, A. (1988). Development and validation of brief measures of positive and negative affect: the PANAS scales. Journal of Personality and Social Psychology, 54(6), 1063–1070.

Visual Analogue Scale to Evaluate Fatigue Severity (vasf)

Eighteen items, each a line from 0 to 10 between two named anchors.

The VAS-F is administered twice — before and after some intervention — and its primary result is the change. It is therefore marked paired; use delta().

Subscale	Items	Direction
Fatigue	1–5, 11–18	higher is more fatigued
Energy	6–10	higher is more energetic
Fatigue (composite)	all 18, energy items reversed	higher is more fatigued

Fatigue and Energy are the instrument’s own two scales, each scored in its own direction. Fatigue (composite) reverse-keys the energy items to give a single number across all eighteen; it is a modelling convenience rather than part of Lee et al.’s scoring, which is why it is named explicitly and tagged at its own level.

Anchor word order differs between item types — “not at all tired” but “keeping my eyes open is no effort at all” — so each item carries its finished prompt. Before 2.0 the caller reassembled these from two dictionaries behind an index-range branch.

Lee, K. A., Hicks, G., & Nino-Murcia, G. (1991). Validity and reliability of a scale to assess fatigue. Psychiatry Research, 36(3), 291–298.

Choosing a Big Five form

All three report the same five domains, in the same order, on the same [0, 1] scale, so they are interchangeable to downstream code.

	Items	Facets	Use when
bfi2	60	yes	Personality is a primary variable
bfi2-xs	15	no	Domain scores suffice and BFI-2 comparability matters
bfi10	10	no	Time is severely constrained

Adding an instrument

Adding one is adding data. Declare the items and subscales, call register(), and import the module from instruments/__init__.py. Registration validates the definition, so a subscale that references a missing item or reverse-keys an item it does not contain fails at import — and therefore in CI — rather than producing a plausible wrong score.