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Currency, unit, scale and decimal precision
Updated 4 August 2026 · 4 min read · 16 Contents
Plain-language meaning
Currency, unit, scale and decimal precision means examining the provenance, timestamps, identity, units, missingness and reproducibility of every market or research observation with the identity, period, unit, source and limitations kept visible. It is a disciplined way to describe evidence, not a shortcut to an investment conclusion.
Learning objectives #
After this chapter you should be able to define currency, unit, scale and decimal precision, identify the evidence needed to use it, distinguish a reported zero from unavailable evidence, and explain why unlike instruments or periods may not be comparable.
Prerequisites #
Read “Exchange identity and symbol collisions” first. Be comfortable checking an exact listing or instrument, its source, observation date, native currency and unit. When any one of those is unknown, pause the comparison and record the gap.
Core concept #
Currency, scale and meaningful decimal precision travel with every numeric value. Preserve raw facts separately from interpretation, and retain the denominator, time window, classification rule and provenance that make the evidence reproducible.
Method #
For currency, unit, scale and decimal precision, first identify the exact evidence named in this chapter: Currency, scale and meaningful decimal precision travel with every numeric value. Then freeze identity and period, collect source-backed inputs with units, calculate or classify only compatible evidence, and record contrary facts and unavailable fields.
Where it appears in XMarketRadar #
Source, retrieved-at, as-of and unavailable labels appear across XMarketRadar. The Help catalogue itself is checked-in editorial data and has no live dependency. A displayed field is useful only with its source and as-of context. If XMarketRadar does not calculate this chapter’s concept directly, use the chapter as an educational checklist and retain the supporting primary document or screen URL in the research workspace.
Worked example #
250 GBp converts to GBP 2.50 at 100:1; a valid 0.004 USD price must not render 0.00. Module context: Illustrative verified close is CU 100 at 16:00 on 3-Aug-2026, retrieved 16:08; a failed 4-Aug fetch retains CU 100 labelled 3-Aug stale or shows —, never a fabricated CU 101. This is an illustrative audit trail, not live data, a target or an expected outcome.
Interpretation #
Interpret the result in the direction defined by the field, not by an assumed desirable outcome. Higher, lower, positive and negative can each have different meanings by context. Compare the observation with its own history or a compatible benchmark, and label conclusions as observations, interpretations or user decisions.
Limitations and common mistakes #
Rounding a non-zero sub-unit value to apparent zero. Providers can revise history, disagree on adjustments, return duplicate dates, omit fields or use timestamps that represent retrieval rather than observation. A precise calculation can still mislead when the source is stale, the denominator changed, or a classification hides important detail.
Market and jurisdiction differences #
Sessions, holidays, symbol systems, licensed fields, decimal scales and corporate-action sources vary. An empty international universe never falls back to another exchange. Exchange rules, accounting conventions, calendars, taxes, disclosure timing, quote scale and licensed coverage can differ. Verify the current primary source for the relevant venue; registry support alone does not prove that every field is available.
Key takeaways #
For currency, unit, scale and decimal precision, remember this boundary: Rounding a non-zero sub-unit value to apparent zero. Keep the evidence exact, dated and source-backed; publish missing information as unavailable rather than manufacturing a value.
Practice #
Reproduce this historical scenario from source-labelled inputs: 250 GBp converts to GBP 2.50 at 100:1; a valid 0.004 USD price must not render 0.00. Then change one input, preserve the original period and unit, and explain whether the result changes or becomes unavailable. Write the identity, source, date, unit and failure condition, then state exactly what would display as —.
Knowledge check #
Reveal answer and explanation
Question: which mistake would invalidate a review of currency, unit, scale and decimal precision? Answer: Rounding a non-zero sub-unit value to apparent zero. Explanation: the chapter requires the stated identity, period, unit and compatible evidence; a missing required input remains — rather than 0.
Educational use only #
This chapter is descriptive education, not investment advice, a forecast, a recommendation, a suitability assessment or an instruction to buy, sell, rebalance, trade or place an order. XMarketRadar’s broker connections remain read-only.