| 1 | aggregate | to combine individual values into a whole | Hard |
| 2 | ascertain | to determine something with reasonable certainty | Hard |
| 3 | benchmark | a reference point used to judge progress | Hard |
| 4 | bias | a systematic influence that distorts a judgment | Hard |
| 5 | calibrate | to adjust an instrument against a standard | Hard |
| 6 | census | a count of every member of a population | Hard |
| 7 | cohort | a group sharing an experience during one period | Hard |
| 8 | confidential | kept from people without permission to know | Hard |
| 9 | control | a condition used to judge the effect of a change | Hard |
| 10 | cross-sectional | comparing groups at one point in time | Hard |
| 11 | denominator | the lower number in a fraction | Hard |
| 12 | deviation | a difference from an expected value or path | Hard |
| 13 | diagnostic | used to identify the source of a problem | Hard |
| 14 | empirical | based on observation or measurement | Hard |
| 15 | extrapolate | to estimate beyond the observed range | Hard |
| 16 | incidence | the rate at which new cases occur | Hard |
| 17 | interval | a space or period between two values | Hard |
| 18 | longitudinal | following the same subjects over time | Hard |
| 19 | magnitude | the size or strength of something | Hard |
| 20 | marginal | small in amount or located at an edge | Hard |
| 21 | metadata | information describing a set of other data | Hard |
| 22 | outlier | a value far from most other values | Hard |
| 23 | prevalence | the share of a group with a condition | Hard |
| 24 | proxy | a substitute measure for something hard to observe | Hard |
| 25 | quantify | to express an amount in numbers | Hard |
| 26 | randomized | assigned by chance to reduce selection bias | Hard |
| 27 | reproducible | able to yield similar results when repeated | Hard |
| 28 | robustness | the ability of a result to hold under changes | Hard |
| 29 | sampling | the selection of a smaller group for study | Hard |
| 30 | sensitivity | how strongly a result changes with an input | Hard |
| 31 | skew | to pull a distribution away from a balanced shape | Hard |
| 32 | stratify | to divide a group into meaningful layers | Hard |
| 33 | threshold | a level at which an effect begins or changes | Hard |
| 34 | triangulate | to check a finding using different methods | Hard |
| 35 | uncertainty | the amount of doubt around an estimate | Hard |
| 36 | variance | a measure of how spread out values are | Hard |
| 37 | comparable | similar enough to support a fair comparison | Hard |
| 38 | generalizable | applicable beyond the particular cases studied | Hard |
| 39 | selection | the process of choosing cases for study | Hard |
| 40 | unobserved | not directly seen or measured | Hard |