How to Read NTEP Ratings

NTEP reports contain excellent turfgrass data, but the tables can be

intimidating when you first encounter them.

A report may contain dozens or hundreds of cultivars, multiple locations,

multiple years, averages, statistical values, and specialized trials.

The key is to avoid treating every number as if it has the same meaning.

Start with the species and trial

First confirm that you are comparing cultivars within the same turfgrass species

and trial.

A Kentucky bluegrass score should not be directly compared with a tall fescue

score simply because both happen to use a 1–9 scale.

NTEP specifically notes that Turfgrass Quality values are relative within a

species and its management context. A quality score of 6 in tall fescue does not

necessarily represent the same turf performance as a 6 in Kentucky bluegrass.

Look at the location

Location is one of the most important columns in an NTEP report.

Climate, soils, rainfall, disease pressure, winter conditions, summer heat and

management vary across test sites. A cultivar may therefore look excellent at

one site and ordinary at another.

NTEP cautions users that results can vary from year to year and location to

location.

This is why PoaIndex retains site-level evidence rather than simply selecting

the cultivar with the highest nationwide average.

Look at the year

A single excellent season is useful evidence, but it is not the same as repeated

performance.

Ask:

How many years was this cultivar evaluated?

How recent are those years?

Does it perform well repeatedly, or only once?

PoaIndex weights recent evidence more heavily while still retaining older

historical results. It also reports confidence separately from performance so

that a cultivar supported by several years and sites can be distinguished from

an impressive result based on sparse evidence.

Understand the 1–9 scale

Many NTEP characteristics use a 1–9 scale.

For Turfgrass Quality, **9 represents outstanding or ideal turf and 1

represents very poor or dead turf. NTEP says a rating of 6 or above is

generally considered acceptable**.

That does not mean you should automatically buy the cultivar with the largest

raw number.

Those scores still need context: location, year, trial, management regime and

statistical separation.

Pay attention to LSD

NTEP tables frequently include an LSD, or Least Significant Difference,

value.

The LSD helps determine whether the observed difference between two cultivar

means is large enough to be statistically distinguishable in that particular

table.

NTEP's guidance is straightforward: compare the difference between two cultivar

means with the LSD. If the difference exceeds the LSD, the difference is

considered statistically significant under that analysis.

For example:

• Cultivar A = 7.0
• Cultivar B = 6.8
• LSD = 0.7

The observed difference is 0.2, which is smaller than the LSD. You should not

interpret that small numeric difference as proof that Cultivar A is meaningfully

superior in that table.

Be careful with rankings

A ranked list is convenient, but rank can exaggerate tiny differences.

Imagine ten cultivars tightly grouped between 6.4 and 6.7. Calling one "#1" and

another "#10" makes the difference sound dramatic even when the underlying

measurements may be effectively similar.

That is one reason PoaIndex keeps the supporting evidence visible rather than

showing a cultivar name without context.

Read specialized tables separately

Current NTEP reports may include specialized sections for conditions such as

traffic, shade, drought, low-input management or different mowing schedules.

Kentucky bluegrass and tall fescue reports, for example, can include specialized

site or management tables in addition to their main Turfgrass Quality analyses.

A cultivar that performs exceptionally under shade should not automatically be

treated as the best general-purpose choice for every lawn.

The rule to remember

**Do not interpret an NTEP number without its species, site, year and test

context.**

That principle is more important than memorizing any particular score.

Next: What Is a Turfgrass Quality Rating?

Sources

• NTEP ratings guidance
• NTEP interpreting data
• Example Kentucky bluegrass quality report