Import Data

 ikea <- read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2020/2020-11-03/ikea.csv')
## New names:
## Rows: 3694 Columns: 14
## ── Column specification
## ──────────────────────────────────────────────────────── Delimiter: "," chr
## (7): name, category, old_price, link, other_colors, short_description, d... dbl
## (6): ...1, item_id, price, depth, height, width lgl (1): sellable_online
## ℹ Use `spec()` to retrieve the full column specification for this data. ℹ
## Specify the column types or set `show_col_types = FALSE` to quiet this message.
## • `` -> `...1`
 skimr::skim(ikea)
Data summary
Name ikea
Number of rows 3694
Number of columns 14
_______________________
Column type frequency:
character 7
logical 1
numeric 6
________________________
Group variables None

Variable type: character

skim_variable n_missing complete_rate min max empty n_unique whitespace
name 0 1 3 27 0 607 0
category 0 1 4 36 0 17 0
old_price 0 1 4 13 0 365 0
link 0 1 52 163 0 2962 0
other_colors 0 1 2 3 0 2 0
short_description 0 1 3 63 0 1706 0
designer 0 1 3 1261 0 381 0

Variable type: logical

skim_variable n_missing complete_rate mean count
sellable_online 0 1 0.99 TRU: 3666, FAL: 28

Variable type: numeric

skim_variable n_missing complete_rate mean sd p0 p25 p50 p75 p100 hist
…1 0 1.00 1846.50 1066.51 0 923.25 1846.5 2769.75 3693 ▇▇▇▇▇
item_id 0 1.00 48632396.79 28887094.10 58487 20390574.00 49288078.0 70403572.75 99932615 ▇▇▇▇▇
price 0 1.00 1078.21 1374.65 3 180.90 544.7 1429.50 9585 ▇▁▁▁▁
depth 1463 0.60 54.38 29.96 1 38.00 47.0 60.00 257 ▇▃▁▁▁
height 988 0.73 101.68 61.10 1 67.00 83.0 124.00 700 ▇▂▁▁▁
width 589 0.84 104.47 71.13 1 60.00 80.0 140.00 420 ▇▅▂▁▁
data <- ikea %>%
  
  na.omit() %>%
  
  # Remove unnecessary columns and treat missing values
  select(-old_price, -link, -...1) %>%
  
  # Handle multiple designers
  separate_rows(designer, sep = "/") %>%
  
  # Convert character variables to factors
  mutate(across(where(is.character), as.factor)) %>%
  mutate(short_description = as.character(short_description)) %>%
  
  # Convert logical variables to factors
  mutate(across(where(is.logical), as.factor)) %>%
  
  # Log transform price (ensure no zero or negative values)
  mutate(price = log(price))

Explore Data

Identify good predictors

# Category
data %>% 
    ggplot(aes(price, category)) +
    geom_boxplot()

# Designer
data %>%
  
    # Tokenize description text
    unnest_tokens(output = word, input = short_description) %>%
    
    # calculate avg rent per word
    group_by(word) %>%
    summarise(price = mean(price),
              n = n()) %>%
    ungroup() %>%
    
    filter(n > 10, !str_detect(word, "\\d")) %>%
    slice_max(order_by = price, n = 10) %>%
    
    # Plot
    ggplot(aes(price, fct_reorder(word, price))) +
    geom_point() +
    
    labs(y = "Products")

EDA shortcut

# Step 1:Prepare data
#Select

#take out short description, and keep designer
data_binarize_tbl <- data %>%
    select(price, height, width, depth, category, other_colors, sellable_online) %>%
    binarize()

data_binarize_tbl %>% glimpse()
## Rows: 2,714
## Columns: 35
## $ `price__-Inf_5.84354441703136`               <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ price__5.84354441703136_6.75693238924755     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ price__6.75693238924755_7.52023455647463     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ price__7.52023455647463_Inf                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `height__-Inf_74`                            <dbl> 0, 1, 0, 0, 0, 0, 0, 0, 0…
## $ height__74_95                                <dbl> 0, 0, 1, 1, 1, 1, 1, 0, 0…
## $ height__95_180.75                            <dbl> 1, 0, 0, 0, 0, 0, 0, 1, 1…
## $ height__180.75_Inf                           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `width__-Inf_60`                             <dbl> 1, 0, 1, 1, 1, 1, 1, 1, 1…
## $ width__60_100                                <dbl> 0, 1, 0, 0, 0, 0, 0, 0, 0…
## $ width__100_180                               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ width__180_Inf                               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `depth__-Inf_40`                             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ depth__40_48                                 <dbl> 0, 0, 1, 1, 1, 1, 1, 1, 1…
## $ depth__48_66                                 <dbl> 1, 1, 0, 0, 0, 0, 0, 0, 0…
## $ depth__66_Inf                                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Bar_furniture                      <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ category__Beds                               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Bookcases_&_shelving_units`       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Cabinets_&_cupboards`             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Café_furniture                     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Chairs                             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Chests_of_drawers_&_drawer_units` <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Children's_furniture`             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Nursery_furniture                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Outdoor_furniture                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Sofas_&_armchairs`                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Tables_&_desks`                   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__TV_&_media_furniture`             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Wardrobes                          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__-OTHER`                           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ other_colors__No                             <dbl> 0, 1, 1, 1, 1, 1, 1, 1, 1…
## $ other_colors__Yes                            <dbl> 1, 0, 0, 0, 0, 0, 0, 0, 0…
## $ sellable_online__TRUE                        <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ `sellable_online__-OTHER`                    <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
# Step 2: Correlate
data_corr_tbl <- data_binarize_tbl %>%
    correlate(price__7.52023455647463_Inf)

data_corr_tbl
## # A tibble: 35 × 3
##    feature  bin                               correlation
##    <fct>    <chr>                                   <dbl>
##  1 price    7.52023455647463_Inf                    1    
##  2 width    180_Inf                                 0.610
##  3 depth    66_Inf                                  0.418
##  4 width    -Inf_60                                -0.356
##  5 category Sofas_&_armchairs                       0.343
##  6 price    -Inf_5.84354441703136                  -0.335
##  7 price    6.75693238924755_7.52023455647463      -0.333
##  8 price    5.84354441703136_6.75693238924755      -0.332
##  9 category Wardrobes                               0.302
## 10 height   -Inf_74                                -0.283
## # ℹ 25 more rows
# Step 3: Plot
data_corr_tbl %>%
    plot_correlation_funnel() 
## Warning: ggrepel: 12 unlabeled data points (too many overlaps). Consider
## increasing max.overlaps

Build Models

Split data

data2 <- data %>%
    select(-other_colors)
# Split into train and test data set
set.seed(1234)
ikea_split <- rsample::initial_split(data2, prop = 0.75)
ikea_train <- training(ikea_split)
ikea_test <- testing(ikea_split)
# Specify recipe
ikea_recipe <- recipe(formula = price ~ ., data = ikea_train) %>%
  update_role(item_id, new_role = "id variable") %>%
  step_tokenize(short_description) %>%
  step_tokenfilter(short_description, max_tokens = 100) %>%  # Missing argument
  step_tfidf(short_description) %>% 
  step_other(category, name, designer, threshold = 0.2) %>%
  step_dummy(all_nominal_predictors()) %>%
  step_log(height, width, depth)

# Now, prep and juice
ikea_recipe %>% prep() %>% juice() %>% glimpse()    
## Rows: 2,035
## Columns: 109
## $ item_id                              <dbl> 9219527, 99248380, 59157555, 1028…
## $ depth                                <dbl> 3.951244, 3.401197, 4.007333, 3.5…
## $ height                               <dbl> 4.454347, 4.820282, 5.375278, 4.4…
## $ width                                <dbl> 3.891820, 5.556828, 5.105945, 3.6…
## $ price                                <dbl> 4.595120, 6.897705, 7.338238, 6.3…
## $ tfidf_short_description_1            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_100x60x236   <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_150x44x236   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_150x58x201   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_150x60x201   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_150x60x236   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_150x66x236   <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_2            <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_200x60x236   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_200x66x236   <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_3            <dbl> 0.0000000, 0.5114545, 0.8524242, …
## $ tfidf_short_description_35x35x35     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_4            <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_41x101       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_41x61        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_5            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_6            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_60x50x128    <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_61x101       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_63           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_74           <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_76           <dbl> 0.000000, 0.000000, 0.000000, 1.1…
## $ tfidf_short_description_8            <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_80x200       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_80x30x202    <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_90           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_90x200       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_add          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_and          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_armchair     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_armrest      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_armrests     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_backrest     <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_bar          <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_baskets      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_bed          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_bedside      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_bench        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_bookcase     <dbl> 0.000, 0.000, 0.000, 0.000, 0.000…
## $ tfidf_short_description_cabinet      <dbl> 0.0000000, 0.5407864, 0.0000000, …
## $ tfidf_short_description_castors      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_chair        <dbl> 2.684967, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_chaise       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_changing     <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_chest        <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ `tfidf_short_description_children's` <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_cm           <dbl> 0.0000000, 0.1776674, 0.2961123, …
## $ tfidf_short_description_combination  <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_corner       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_cover        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_day          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_desk         <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_door         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_doors        <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_drawer       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_drawers      <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_feet         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_foldable     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_for          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_frame        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_glass        <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_highchair    <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_in           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_inserts      <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_junior       <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_leg          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_legs         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_lock         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_longue       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_mesh         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_modular      <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_module       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_mounted      <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_of           <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_on           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_outdoor      <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_panel        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_plinth       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_seat         <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_section      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_sections     <dbl> 0.0000000, 0.7998332, 1.3330553, …
## $ tfidf_short_description_shelf        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_shelves      <dbl> 0.0000000, 0.7666921, 0.0000000, …
## $ tfidf_short_description_shelving     <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_side         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_sliding      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_smart        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_sofa         <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_stool        <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_storage      <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_table        <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_top          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_tv           <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_unit         <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_upright      <dbl> 0.000000, 0.000000, 0.000000, 0.0…
## $ tfidf_short_description_w            <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_wall         <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_wardrobe     <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ tfidf_short_description_wire         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, …
## $ tfidf_short_description_with         <dbl> 0.0000000, 0.0000000, 0.0000000, …
## $ name_other                           <dbl> 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, …
## $ category_other                       <dbl> 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, …
## $ sellable_online_TRUE.                <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, …
## $ designer_other                       <dbl> 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, …
# Specify model
xgboost_spec <- 
  boost_tree(trees = tune(), min_n = tune(), mtry = tune(), learn_rate = tune())%>% 
  set_mode("regression") %>% 
  set_engine("xgboost") 

# Combine recipe and model using workflow
xgboost_workflow <- 
  workflow() %>% 
  add_recipe(ikea_recipe) %>% 
  add_model(xgboost_spec) 

# Create cross-validation folds
set.seed(2345)
ikea_cv <- vfold_cv(ikea_train, v = 5)

# Tune hyperperameters
set.seed(3456)
xgboost_tune <-
  tune_grid(xgboost_workflow, 
            resamples = ikea_cv, 
            grid = 10)
## i Creating pre-processing data to finalize unknown parameter: mtry

Evaluate Models

# Show the best hyperparameters based on RMSE
tune::show_best(xgboost_tune, metric = "rmse")
## # A tibble: 5 × 10
##    mtry trees min_n learn_rate .metric .estimator  mean     n std_err .config   
##   <int> <int> <int>      <dbl> <chr>   <chr>      <dbl> <int>   <dbl> <chr>     
## 1    56  1741     3     0.0868 rmse    standard   0.316     5 0.0163  Preproces…
## 2    80   922    22     0.204  rmse    standard   0.331     5 0.0166  Preproces…
## 3    13  1578    15     0.130  rmse    standard   0.334     5 0.0124  Preproces…
## 4    65   656    18     0.0521 rmse    standard   0.353     5 0.0135  Preproces…
## 5    42  1808    39     0.0128 rmse    standard   0.386     5 0.00960 Preproces…
# Update de model by selecting the best hyperparameter
xgboost_fw <- tune::finalize_workflow(xgboost_workflow,
                        tune::select_best(xgboost_tune, metric = "rmse"))

# Fit the model on the entire training data and test it on the test data
ikea_fit <- tune::last_fit(xgboost_fw, ikea_split)

tune::collect_metrics(ikea_fit)
## # A tibble: 2 × 4
##   .metric .estimator .estimate .config             
##   <chr>   <chr>          <dbl> <chr>               
## 1 rmse    standard       0.267 Preprocessor1_Model1
## 2 rsq     standard       0.952 Preprocessor1_Model1
tune::collect_predictions(ikea_fit) %>%
    ggplot(aes(price, .pred)) +
    geom_point(alpha = 0.3, color = "purple4") +
    geom_abline(lty = 2, color = "gray30") +
    coord_fixed()

Make Prediction

Throughout the model refinement process, I experimented with various parameters, including tinker with threshold, max_token, and grid, to optimize performance. Initially, adjusting threshold to 0.05 improved RMSE but slightly worsened R-squared. Increasing threshold to 0.2 resulted in a worse RMSE while keeping R-squared unchanged. Lowering max_token to 50 yielded worse results, while reverting to 100 improved both metrics. Switching the grid to 10 further enhanced performance.