National Merit: The Selection Index
The one number the SAT has no version of, why Reading and Writing counts twice inside it, and how that single fact rewrites a study plan.
7 topics · 28 questions
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The Selection Index and Its 48 to 228 Scale
- How it worksHow does the Selection Index formula fold two section scores into one number between 48 and 228?
- Worked exampleFind the Selection Index of a PSAT scorer with Reading and Writing 620 and Math 500.
- Common mistakeWhy doesn't the Selection Index scale start at zero, and where does its floor of 48 come from?
- Going furtherWhat happens at the very top of the scale, where 760 and 760 has to land exactly on 228?
Your turneasy1 of 3
Find the Selection Index of a PSAT scorer with Reading and Writing 650 and Math 620.Why Reading and Writing Is Double-Weighted
- How it worksHow does doubling the Reading and Writing section make one point there worth two points of Math?
- Worked exampleFind the Selection Index for 700 Reading and Writing with 640 Math, then swap the two scores and compare.
- Common mistakeWhy isn't a 1340 PSAT always the same shot at National Merit no matter which section carried it?
- Going furtherWhat happens to your Index when 30 points move out of Math and into Reading and Writing?
- Going furtherWhat happens to the double-weight advantage once Reading and Writing runs into its 760 ceiling?
Your turneasy1 of 3
One student scores Reading and Writing 710 with Math 500; another has exactly the reverse split. Find how many Selection Index points separate them.Computing Your Index From a Score Report
- How it worksHow do you read the two section scores off a PSAT report and turn them into one Selection Index?
- Worked exampleFind the Selection Index for a report showing Reading and Writing 710 and Math 680.
- Worked exampleFind the Reading and Writing score a student needs for a 210 Index when Math is locked at 680.
Your turneasy1 of 3
A PSAT score report shows Reading and Writing 700 and Math 670. Find the Selection Index it prints.Why the Index Is Not the Total Score
- How it worksHow does the Index reward a lopsided score while the total treats both sections the same?
- Worked exampleFind both Selection Indexes for 730 Reading and Writing with 660 Math and for the reverse split.
- Common mistakeWhy isn't trading PSAT totals with a friend a fair way to compare National Merit chances?
- Ties togetherHow does the gap between total score and Selection Index change where a state cutoff actually bites?
Your turneasy1 of 3
Two students both total 1270 on the PSAT. One scores Reading and Writing 720 and the other scores Reading and Writing 600. Find the difference between their Selection Indexes.Where the Last Month of Study Goes
- How it worksHow do you turn expected point gains per hour into expected Selection Index gain per hour?
- Worked exampleFind which section to study when 10 hours buys 20 Math points or 12 Reading and Writing points.
- Worked exampleFind the break-even point where Math practice finally beats Reading and Writing practice for the Index.
- Common mistakeWhy doesn't the usual advice to drill your weakest section hold when the target is a Selection Index?
- Going furtherWhat changes about the trade-off when Reading and Writing already sits at 750 and Math sits at 600?
Your turnmedium1 of 3
15 hours of study is expected to buy either 40 Math points or 50 Reading and Writing points. Find how many MORE Selection Index points the Reading and Writing option is worth; a negative answer means Math wins.Turning a Cutoff Into a Points Target
- How it worksHow do you convert a gap of 6 Selection Index points into the section points you still have to find?
- Worked exampleFind what a 202 scorer needs in each section separately to reach a cutoff of 219.
- Worked exampleFind the cheapest split of gains that carries a 660 and 640 PSAT from 196 up to the 208 Commended level.
- Common mistakeWhy doesn't adding 20 points to each section add 20 points to your Selection Index?
Your turneasy1 of 3
A student's Selection Index is 200 and their state's Semifinalist cutoff is 218. Find how many READING AND WRITING points they would need to gain if the whole gain came from that section.The Score Range Around Your Index
- How it worksHow does the standard error on each section widen into a whole band around your Selection Index?
- Worked exampleFind the Index band when Reading and Writing 700 and Math 690 each carry a range of 20 points.
- Common mistakeWhy isn't landing one point under a cutoff the same as being one point short of that ability?
Your turneasy1 of 3
A report gives Reading and Writing 680 and Math 660, each with a range of plus or minus 40 points. Find the WIDTH of the resulting Selection Index band, highest minus lowest.AP®, SAT® and PSAT/NMSQT® are trademarks registered by the College Board (PSAT/NMSQT® jointly with the National Merit Scholarship Corporation). ACT® is a registered trademark of ACT Education Corp. GRE® is a registered trademark of ETS. LSAT® is a registered trademark of the Law School Admission Council. MCAT® is a registered trademark of the Association of American Medical Colleges. ISEE® and SSAT® are registered trademarks of their owners. None of these organizations is affiliated with, or endorses, Jentoo.