library(tidyverse)
## ── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
## ✔ dplyr     1.1.4     ✔ readr     2.1.5
## ✔ forcats   1.0.0     ✔ stringr   1.5.1
## ✔ ggplot2   3.5.1     ✔ tibble    3.2.1
## ✔ lubridate 1.9.3     ✔ tidyr     1.3.1
## ✔ purrr     1.0.2     
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## ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors
attrition_raw_tbl <- read_csv("00_data/WA_Fn-UseC_-HR-Employee-Attrition.csv")
## Rows: 1470 Columns: 35
## ── Column specification ────────────────────────────────────────────────────────
## Delimiter: ","
## chr  (9): Attrition, BusinessTravel, Department, EducationField, Gender, Job...
## dbl (26): Age, DailyRate, DistanceFromHome, Education, EmployeeCount, Employ...
## 
## 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.
attrition_raw_tbl %>% glimpse()
## Rows: 1,470
## Columns: 35
## $ Age                      <dbl> 41, 49, 37, 33, 27, 32, 59, 30, 38, 36, 35, 2…
## $ Attrition                <chr> "Yes", "No", "Yes", "No", "No", "No", "No", "…
## $ BusinessTravel           <chr> "Travel_Rarely", "Travel_Frequently", "Travel…
## $ DailyRate                <dbl> 1102, 279, 1373, 1392, 591, 1005, 1324, 1358,…
## $ Department               <chr> "Sales", "Research & Development", "Research …
## $ DistanceFromHome         <dbl> 1, 8, 2, 3, 2, 2, 3, 24, 23, 27, 16, 15, 26, …
## $ Education                <dbl> 2, 1, 2, 4, 1, 2, 3, 1, 3, 3, 3, 2, 1, 2, 3, …
## $ EducationField           <chr> "Life Sciences", "Life Sciences", "Other", "L…
## $ EmployeeCount            <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, …
## $ EmployeeNumber           <dbl> 1, 2, 4, 5, 7, 8, 10, 11, 12, 13, 14, 15, 16,…
## $ EnvironmentSatisfaction  <dbl> 2, 3, 4, 4, 1, 4, 3, 4, 4, 3, 1, 4, 1, 2, 3, …
## $ Gender                   <chr> "Female", "Male", "Male", "Female", "Male", "…
## $ HourlyRate               <dbl> 94, 61, 92, 56, 40, 79, 81, 67, 44, 94, 84, 4…
## $ JobInvolvement           <dbl> 3, 2, 2, 3, 3, 3, 4, 3, 2, 3, 4, 2, 3, 3, 2, …
## $ JobLevel                 <dbl> 2, 2, 1, 1, 1, 1, 1, 1, 3, 2, 1, 2, 1, 1, 1, …
## $ JobRole                  <chr> "Sales Executive", "Research Scientist", "Lab…
## $ JobSatisfaction          <dbl> 4, 2, 3, 3, 2, 4, 1, 3, 3, 3, 2, 3, 3, 4, 3, …
## $ MaritalStatus            <chr> "Single", "Married", "Single", "Married", "Ma…
## $ MonthlyIncome            <dbl> 5993, 5130, 2090, 2909, 3468, 3068, 2670, 269…
## $ MonthlyRate              <dbl> 19479, 24907, 2396, 23159, 16632, 11864, 9964…
## $ NumCompaniesWorked       <dbl> 8, 1, 6, 1, 9, 0, 4, 1, 0, 6, 0, 0, 1, 0, 5, …
## $ Over18                   <chr> "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", …
## $ OverTime                 <chr> "Yes", "No", "Yes", "Yes", "No", "No", "Yes",…
## $ PercentSalaryHike        <dbl> 11, 23, 15, 11, 12, 13, 20, 22, 21, 13, 13, 1…
## $ PerformanceRating        <dbl> 3, 4, 3, 3, 3, 3, 4, 4, 4, 3, 3, 3, 3, 3, 3, …
## $ RelationshipSatisfaction <dbl> 1, 4, 2, 3, 4, 3, 1, 2, 2, 2, 3, 4, 4, 3, 2, …
## $ StandardHours            <dbl> 80, 80, 80, 80, 80, 80, 80, 80, 80, 80, 80, 8…
## $ StockOptionLevel         <dbl> 0, 1, 0, 0, 1, 0, 3, 1, 0, 2, 1, 0, 1, 1, 0, …
## $ TotalWorkingYears        <dbl> 8, 10, 7, 8, 6, 8, 12, 1, 10, 17, 6, 10, 5, 3…
## $ TrainingTimesLastYear    <dbl> 0, 3, 3, 3, 3, 2, 3, 2, 2, 3, 5, 3, 1, 2, 4, …
## $ WorkLifeBalance          <dbl> 1, 3, 3, 3, 3, 2, 2, 3, 3, 2, 3, 3, 2, 3, 3, …
## $ YearsAtCompany           <dbl> 6, 10, 0, 8, 2, 7, 1, 1, 9, 7, 5, 9, 5, 2, 4,…
## $ YearsInCurrentRole       <dbl> 4, 7, 0, 7, 2, 7, 0, 0, 7, 7, 4, 5, 2, 2, 2, …
## $ YearsSinceLastPromotion  <dbl> 0, 1, 0, 3, 2, 3, 0, 0, 1, 7, 0, 0, 4, 1, 0, …
## $ YearsWithCurrManager     <dbl> 5, 7, 0, 0, 2, 6, 0, 0, 8, 7, 3, 8, 3, 2, 3, …

Prompt 1

The goal is to help predict attrition for employees.

Please write R code to create a predictive model that predicts the probability of attrition.

# Load libraries
library(tidyverse)
library(caret)
## Loading required package: lattice
## 
## Attaching package: 'caret'
## The following object is masked from 'package:purrr':
## 
##     lift
library(e1071)
library(pROC)
## Type 'citation("pROC")' for a citation.
## 
## Attaching package: 'pROC'
## The following objects are masked from 'package:stats':
## 
##     cov, smooth, var
# Step 1: Preprocessing
# Convert character columns to factors
attrition_tbl <- attrition_raw_tbl %>%
  mutate_if(is.character, as.factor) %>%
  select(-EmployeeCount, -StandardHours, -Over18, -EmployeeNumber)  # Remove constant or ID columns

# Step 2: Train/test split (80/20)
set.seed(123)
split <- createDataPartition(attrition_tbl$Attrition, p = 0.8, list = FALSE)
train_tbl <- attrition_tbl[split, ]
test_tbl <- attrition_tbl[-split, ]

# Step 3: Train logistic regression model
model_glm <- glm(Attrition ~ ., data = train_tbl, family = "binomial")

# Step 4: Evaluate model
# Predict probabilities
test_probs <- predict(model_glm, newdata = test_tbl, type = "response")

# Predict classes
test_pred <- ifelse(test_probs > 0.5, "Yes", "No") %>% factor(levels = c("No", "Yes"))

# Confusion matrix
confusionMatrix(test_pred, test_tbl$Attrition)
## Confusion Matrix and Statistics
## 
##           Reference
## Prediction  No Yes
##        No  236  30
##        Yes  10  17
##                                           
##                Accuracy : 0.8635          
##                  95% CI : (0.8188, 0.9006)
##     No Information Rate : 0.8396          
##     P-Value [Acc > NIR] : 0.149962        
##                                           
##                   Kappa : 0.3878          
##                                           
##  Mcnemar's Test P-Value : 0.002663        
##                                           
##             Sensitivity : 0.9593          
##             Specificity : 0.3617          
##          Pos Pred Value : 0.8872          
##          Neg Pred Value : 0.6296          
##              Prevalence : 0.8396          
##          Detection Rate : 0.8055          
##    Detection Prevalence : 0.9078          
##       Balanced Accuracy : 0.6605          
##                                           
##        'Positive' Class : No              
## 
# AUC
roc_obj <- roc(test_tbl$Attrition, test_probs)
## Setting levels: control = No, case = Yes
## Setting direction: controls < cases
auc(roc_obj)
## Area under the curve: 0.8432
# Step 5: Predict on new data (example)
# predict(model_glm, newdata = new_employee_data, type = "response")

Prompt 2:

Please update the code to use tidymodels instead of caret and to use the h2o model instead of glmnet.

# Load libraries
library(tidymodels)
## ── Attaching packages ────────────────────────────────────── tidymodels 1.2.0 ──
## ✔ broom        1.0.7     ✔ rsample      1.2.1
## ✔ dials        1.4.0     ✔ tune         1.2.1
## ✔ infer        1.0.7     ✔ workflows    1.1.4
## ✔ modeldata    1.4.0     ✔ workflowsets 1.1.0
## ✔ parsnip      1.3.0     ✔ yardstick    1.3.2
## ✔ recipes      1.1.0
## ── Conflicts ───────────────────────────────────────── tidymodels_conflicts() ──
## ✖ scales::discard()        masks purrr::discard()
## ✖ dplyr::filter()          masks stats::filter()
## ✖ recipes::fixed()         masks stringr::fixed()
## ✖ dplyr::lag()             masks stats::lag()
## ✖ caret::lift()            masks purrr::lift()
## ✖ rsample::permutations()  masks e1071::permutations()
## ✖ yardstick::precision()   masks caret::precision()
## ✖ yardstick::recall()      masks caret::recall()
## ✖ yardstick::sensitivity() masks caret::sensitivity()
## ✖ yardstick::spec()        masks readr::spec()
## ✖ yardstick::specificity() masks caret::specificity()
## ✖ recipes::step()          masks stats::step()
## ✖ tune::tune()             masks parsnip::tune(), e1071::tune()
## • Learn how to get started at https://www.tidymodels.org/start/
library(h2o)
## 
## ----------------------------------------------------------------------
## 
## Your next step is to start H2O:
##     > h2o.init()
## 
## For H2O package documentation, ask for help:
##     > ??h2o
## 
## After starting H2O, you can use the Web UI at http://localhost:54321
## For more information visit https://docs.h2o.ai
## 
## ----------------------------------------------------------------------
## 
## Attaching package: 'h2o'
## The following object is masked from 'package:pROC':
## 
##     var
## The following objects are masked from 'package:lubridate':
## 
##     day, hour, month, week, year
## The following objects are masked from 'package:stats':
## 
##     cor, sd, var
## The following objects are masked from 'package:base':
## 
##     &&, %*%, %in%, ||, apply, as.factor, as.numeric, colnames,
##     colnames<-, ifelse, is.character, is.factor, is.numeric, log,
##     log10, log1p, log2, round, signif, trunc
library(janitor)
## 
## Attaching package: 'janitor'
## The following objects are masked from 'package:stats':
## 
##     chisq.test, fisher.test
library(dplyr)

# Initialize H2O
h2o.init()
##  Connection successful!
## 
## R is connected to the H2O cluster: 
##     H2O cluster uptime:         6 minutes 1 seconds 
##     H2O cluster timezone:       America/New_York 
##     H2O data parsing timezone:  UTC 
##     H2O cluster version:        3.44.0.3 
##     H2O cluster version age:    1 year, 4 months and 14 days 
##     H2O cluster name:           H2O_started_from_R_aldendimick_ggl822 
##     H2O cluster total nodes:    1 
##     H2O cluster total memory:   3.54 GB 
##     H2O cluster total cores:    8 
##     H2O cluster allowed cores:  8 
##     H2O cluster healthy:        TRUE 
##     H2O Connection ip:          localhost 
##     H2O Connection port:        54321 
##     H2O Connection proxy:       NA 
##     H2O Internal Security:      FALSE 
##     R Version:                  R version 4.4.1 (2024-06-14)
## Warning in h2o.clusterInfo(): 
## Your H2O cluster version is (1 year, 4 months and 14 days) old. There may be a newer version available.
## Please download and install the latest version from: https://h2o-release.s3.amazonaws.com/h2o/latest_stable.html
# Step 1: Read data
attrition_raw_tbl <- read_csv("00_data/WA_Fn-UseC_-HR-Employee-Attrition.csv")
## Rows: 1470 Columns: 35
## ── Column specification ────────────────────────────────────────────────────────
## Delimiter: ","
## chr  (9): Attrition, BusinessTravel, Department, EducationField, Gender, Job...
## dbl (26): Age, DailyRate, DistanceFromHome, Education, EmployeeCount, Employ...
## 
## 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.
# Step 2: Clean and prepare
attrition_tbl <- attrition_raw_tbl %>%
  clean_names() %>%
  mutate(attrition = factor(attrition, levels = c("No", "Yes")))

# Step 3: Split data
set.seed(123)
attrition_split <- initial_split(attrition_tbl, prop = 0.8, strata = attrition)
attrition_train <- training(attrition_split)
attrition_test  <- testing(attrition_split)

# Step 4: Recipe
attrition_recipe <- recipe(attrition ~ ., data = attrition_train) %>%
  update_role(employee_number, new_role = "ID") %>%
  step_rm(employee_count, over18, standard_hours) %>%
  step_zv(all_predictors()) %>%
  step_dummy(all_nominal_predictors()) %>%
  step_normalize(all_numeric_predictors())

# Step 5: Prep and juice the data
prepped_recipe <- prep(attrition_recipe)
train_juiced   <- juice(prepped_recipe)
test_baked     <- bake(prepped_recipe, new_data = attrition_test)

# Step 6: Convert to H2O frame
train_h2o <- as.h2o(train_juiced)
##   |                                                                              |                                                                      |   0%  |                                                                              |======================================================================| 100%
test_h2o  <- as.h2o(test_baked)
##   |                                                                              |                                                                      |   0%  |                                                                              |======================================================================| 100%
# Step 7: H2O model training (AutoML or GBM as example)
automl_model <- h2o.automl(
  x = setdiff(names(train_h2o), c("attrition", "employee_number")),
  y = "attrition",
  training_frame = train_h2o,
  max_runtime_secs = 30,
  balance_classes = TRUE,
  seed = 123
)
##   |                                                                              |                                                                      |   0%  |                                                                              |==                                                                    |   4%
## 09:49:04.779: AutoML: XGBoost is not available; skipping it.  |                                                                              |=======                                                               |  10%  |                                                                              |=============                                                         |  18%  |                                                                              |==================                                                    |  26%  |                                                                              |=====================                                                 |  31%  |                                                                              |==========================                                            |  37%  |                                                                              |===============================                                       |  44%  |                                                                              |====================================                                  |  51%  |                                                                              |========================================                              |  58%  |                                                                              |=============================================                         |  64%  |                                                                              |==================================================                    |  71%  |                                                                              |======================================================                |  78%  |                                                                              |===========================================================           |  85%  |                                                                              |================================================================      |  91%  |                                                                              |===================================================================== |  98%  |                                                                              |======================================================================| 100%
# Step 8: Make predictions
preds <- h2o.predict(automl_model@leader, test_h2o)
##   |                                                                              |                                                                      |   0%  |                                                                              |======================================================================| 100%
preds_df <- as.data.frame(preds)

# Step 9: Combine with actuals
results <- bind_cols(
  attrition = test_baked$attrition,
  predicted_class = preds_df$predict,
  prob_no = preds_df$No,
  prob_yes = preds_df$Yes
)

# Accuracy and other metrics
results_metrics <- metrics(results, truth = attrition, estimate = predicted_class)

# AUC
auc_value <- roc_auc(results, truth = attrition, prob_yes)

# Print
print(results_metrics)
## # A tibble: 2 × 3
##   .metric  .estimator .estimate
##   <chr>    <chr>          <dbl>
## 1 accuracy binary         0.898
## 2 kap      binary         0.614
print(auc_value)
## # A tibble: 1 × 3
##   .metric .estimator .estimate
##   <chr>   <chr>          <dbl>
## 1 roc_auc binary        0.0957

Prompt 3:

Error in .h2o.doSafeREST(h2oRestApiVersion = h2oRestApiVersion, urlSuffix = page, :

h2o.shutdown(prompt = FALSE)
Sys.sleep(5) # Give it time to shut down
h2o.init()
## 
## H2O is not running yet, starting it now...
## 
## Note:  In case of errors look at the following log files:
##     /var/folders/kp/5ph4v9l12gq3j0pgz0gd8txr0000gn/T//RtmpYlaUOS/file8cf42d0e55f/h2o_aldendimick_started_from_r.out
##     /var/folders/kp/5ph4v9l12gq3j0pgz0gd8txr0000gn/T//RtmpYlaUOS/file8cf46082c16a/h2o_aldendimick_started_from_r.err
## 
## 
## Starting H2O JVM and connecting: .. Connection successful!
## 
## R is connected to the H2O cluster: 
##     H2O cluster uptime:         2 seconds 318 milliseconds 
##     H2O cluster timezone:       America/New_York 
##     H2O data parsing timezone:  UTC 
##     H2O cluster version:        3.44.0.3 
##     H2O cluster version age:    1 year, 4 months and 14 days 
##     H2O cluster name:           H2O_started_from_R_aldendimick_ggl822 
##     H2O cluster total nodes:    1 
##     H2O cluster total memory:   3.54 GB 
##     H2O cluster total cores:    8 
##     H2O cluster allowed cores:  8 
##     H2O cluster healthy:        TRUE 
##     H2O Connection ip:          localhost 
##     H2O Connection port:        54321 
##     H2O Connection proxy:       NA 
##     H2O Internal Security:      FALSE 
##     R Version:                  R version 4.4.1 (2024-06-14)
## Warning in h2o.clusterInfo(): 
## Your H2O cluster version is (1 year, 4 months and 14 days) old. There may be a newer version available.
## Please download and install the latest version from: https://h2o-release.s3.amazonaws.com/h2o/latest_stable.html
attrition_raw_tbl <- attrition_raw_tbl %>%
  mutate_if(is.character, as.factor) # H2O prefers factors for classification

attrition_h2o <- as.h2o(attrition_raw_tbl)
##   |                                                                              |                                                                      |   0%  |                                                                              |======================================================================| 100%
h2o::h2o.clusterInfo()
## R is connected to the H2O cluster: 
##     H2O cluster uptime:         2 seconds 981 milliseconds 
##     H2O cluster timezone:       America/New_York 
##     H2O data parsing timezone:  UTC 
##     H2O cluster version:        3.44.0.3 
##     H2O cluster version age:    1 year, 4 months and 14 days 
##     H2O cluster name:           H2O_started_from_R_aldendimick_ggl822 
##     H2O cluster total nodes:    1 
##     H2O cluster total memory:   3.54 GB 
##     H2O cluster total cores:    8 
##     H2O cluster allowed cores:  8 
##     H2O cluster healthy:        TRUE 
##     H2O Connection ip:          localhost 
##     H2O Connection port:        54321 
##     H2O Connection proxy:       NA 
##     H2O Internal Security:      FALSE 
##     R Version:                  R version 4.4.1 (2024-06-14)
## Warning in h2o::h2o.clusterInfo(): 
## Your H2O cluster version is (1 year, 4 months and 14 days) old. There may be a newer version available.
## Please download and install the latest version from: https://h2o-release.s3.amazonaws.com/h2o/latest_stable.html

Prompt 4:

Please update the code to use h2o.performance in Step 5, instead of mean.

# Step 1: Load libraries and initialize H2O
library(h2o)
h2o.init()
##  Connection successful!
## 
## R is connected to the H2O cluster: 
##     H2O cluster uptime:         3 seconds 4 milliseconds 
##     H2O cluster timezone:       America/New_York 
##     H2O data parsing timezone:  UTC 
##     H2O cluster version:        3.44.0.3 
##     H2O cluster version age:    1 year, 4 months and 14 days 
##     H2O cluster name:           H2O_started_from_R_aldendimick_ggl822 
##     H2O cluster total nodes:    1 
##     H2O cluster total memory:   3.54 GB 
##     H2O cluster total cores:    8 
##     H2O cluster allowed cores:  8 
##     H2O cluster healthy:        TRUE 
##     H2O Connection ip:          localhost 
##     H2O Connection port:        54321 
##     H2O Connection proxy:       NA 
##     H2O Internal Security:      FALSE 
##     R Version:                  R version 4.4.1 (2024-06-14)
## Warning in h2o.clusterInfo(): 
## Your H2O cluster version is (1 year, 4 months and 14 days) old. There may be a newer version available.
## Please download and install the latest version from: https://h2o-release.s3.amazonaws.com/h2o/latest_stable.html
# Step 2: Convert data
attrition_raw_tbl <- attrition_raw_tbl %>%
  mutate_if(is.character, as.factor)

attrition_h2o <- as.h2o(attrition_raw_tbl)
##   |                                                                              |                                                                      |   0%  |                                                                              |======================================================================| 100%
# Step 3: Split data
splits <- h2o.splitFrame(data = attrition_h2o, ratios = 0.7, seed = 1234)
train <- splits[[1]]
test <- splits[[2]]

# Step 4: Train model
model <- h2o.gbm(
  x = setdiff(names(attrition_h2o), c("Attrition")),
  y = "Attrition",
  training_frame = train,
  ntrees = 50,
  max_depth = 5,
  learn_rate = 0.1,
  seed = 1234
)
## Warning in .h2o.processResponseWarnings(res): Dropping bad and constant columns: [StandardHours, EmployeeCount, Over18].
##   |                                                                              |                                                                      |   0%  |                                                                              |======================================================================| 100%
# Step 5: Evaluate model
# Old (using mean): 
# mean(h2o.predict(model, test) == test$Attrition)

# Step 5: Evaluate model with h2o.performance
perf <- h2o.performance(model, newdata = test)

# For classification models:
h2o.auc(perf)           # Area under the ROC curve
## [1] 0.793594
h2o.accuracy(perf)      # Accuracy
##   threshold  accuracy
## 1 0.8650728 0.8465116
## 2 0.8217769 0.8488372
## 3 0.8003270 0.8511628
## 4 0.7914861 0.8534884
## 5 0.7559341 0.8558140
## 
## ---
##       threshold  accuracy
## 395 0.009951674 0.1674419
## 396 0.009491380 0.1651163
## 397 0.008732425 0.1627907
## 398 0.008042115 0.1604651
## 399 0.007795504 0.1581395
## 400 0.006920223 0.1558140
h2o.confusionMatrix(perf)  # Confusion matrix
## Confusion Matrix (vertical: actual; across: predicted)  for max f1 @ threshold = 0.138644269184748:
##         No Yes    Error     Rate
## No     282  81 0.223140  =81/363
## Yes     18  49 0.268657   =18/67
## Totals 300 130 0.230233  =99/430