Island Evaluations

Island evaluation is a service in New Horizons offered by Isabelle at Resident Services after the player completes the campsite on the deserted island and the first campsite visitor finishes moving in as a resident. The task force to survey island residents and visitors, Isabelle scores the island's popularity on a scale of 1 to 5 stars. Source: Fandom.com

Unlock

After achieving a 3-star rating for the first time, Tom Nook ends Project K by asking K.K. Slider to hold a concert on the island. K.K.'s concert occurs the next day, or on the day after any pre-scheduled event, after which Tom Nook presents the player with the Island Designer app and K.K. visits the island every Saturday or Sunday (formerly Friday).

After achieving a 5-star rating for the first time, Isabelle rewards the player with the DIY recipe for the golden watering can and one lily-of-the-valley spawns on the island every week as long as the rating holds.

Point System

Flowers and Trees (Scenery Points)

• Trees are 1 point, and bushes are worth 0.5 points each. The combined sum of these two values cannot exceed 190.
• Flower Sprouts are 0.5 points each.
• Flower Buds and Flower stems are 0.7 points each.
• Adult flowers are 1 point each.

DIY Furniture Around the Island (Scenery Points)

• Furniture placed is graded on an 8×8-tile basis known as a block.
• Each unique piece of furniture that is 3×1, 3×2, or 3×3 tile size is 1 point.
• Furniture points are calculated using the number of furniture placed × 0.25 and if you have more than 10 unique types you get a bonus of the number of types × 0.75.

Buildings and Sructures (Developemental Points)

• The Museum, Nook's Cranny, and Able Sisters are all worth 15 points each.
• Each bridge and incline is worth 15 points each.

Decorating with Other Furniture (both DIY and catalogable) (Developemental Points)

• Furniture placed is graded on an 8×8-tile basis known as a block.
• If there are fewer than 5 unique types of furniture placed: number of pieces of furniture × 1.
• If there are 5 to 10 unique types of furniture placed: number of pieces of furniture × 0.5 + number of types of furniture × 0.5.
• If there are greater than 10 unique types of furniture placed: number of pieces of furniture × 0.25 + number of types of furniture × 0.75.
• If 6+ of the same item in the block, all extra copies of any item lose 0.5 points each. If 11+ of the same item in the block, extra copies of any item lose 0.75 points each.

Weeds (Developemental Points): When there are 100 weeds or fewer on a given island, a bonus of 30 development points are given to the island. Past 100 weeds on a given island, a bonus of (1000 − weeds) / 30 points are given to the island.

Villagers (Developemental Points): There is a development bonus of 15 points if there are nine villagers, and a development bonus of 30 points for 10 villagers.

Negative Conditions

These conditions must be met to get to 5 stars.

Too Rural: 220+ Trees. Isabelle reports the "overabundance of trees" and "people getting lost in the woods and fearing for the worst". This can be solved by digging up or cutting down trees until the total number of trees falls below the limit.

Traffic hazard: Traffic hazard is gauged in the same 8×8-tile divisions as furniture. If 45+ of 64 tiles are covered in the block, Isabelle reports "freely moving around" is important. Buildings, bridges, buried items, rocks, cliffs, rivers, and inclines do not count towards this.

Clutter:

• If there are 10+ of certain items dropped on the ground, Isabelle reports there are "too many items lying around". Items that are dropped onto furniture as well as the message bottles on the shore used to penalize the rating. Items the island natively drops—tree branches, stones, shells, and message bottles—and planted and dropped weeds and meteorites are exempt.
• All other items that come from player interaction of food such as fruit, turnips, bamboo shoots, eggs, candy, and mushrooms, seeds such as packets, acorns, and pine cones, floral droppings such as blossoms, petals, and wasp nests, timber such as wood and bamboo, minerals such as clay, nuggets, and pearls, bells, paper such as DIYs, tickets, and wrapping paper, packages such as presents, fish bait, and medicine, forgotten lost items, clothing, trash, props such as flooring, wallpaper, and handwares, tools, furniture, and fossils must be dropped onto furniture such as a zen cushion, stool, critter case or tank, bench, table, stall, refrigerator, or vending machine to avoid clutter. Presents from balloons and newly-lost items never land on furniture and can't be dropped.