我正在训练分类器来预测哪个分类器将基于文本的请求分类到部门。我有~107,000个由22个不平衡类组成的标记示例，大致有以下分布：
我一直在预处理数据，以提供偶数个样本（每个类有5,000个样本到50,000个样本）。其中上述分类器和平衡训练数据，我能够在测试数据上获得高达98.5％的准确度，总训练数据为50-50。但是当新请求进入并加载分类器时，分类器最多只能达到50-70％的准确率。样本相对稳定，相同的请求总是发送到同一个部门，所以我非常惊讶，只有50-70％的准确度，特别是在测试数据上具有如此高的准确度：
import logging
import os
from sklearn.preprocessing import LabelEncoder
from sklearn.ensemble import RandomForestClassifier
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.pipeline import Pipeline
from sklearn.model_selection import train_test_split
from sklearn.model_selection import cross_val_score
from sklearn.externals import joblib
from sklearn.metrics import classification_report
logger = logging.getLogger(__name__)
def up_sample(data, labels, **kwargs):
label_counts = Counter(labels)
max_label = max(label_counts, key=label_counts.get)
max_label_count = kwargs.get('samples', label_counts[max_label])
output_text = []
output_labels = []
for label, count in label_counts.items():
label_text = [data_row for data_row, label_row in zip(data, labels) if label_row == label]
resampled_labels = [label] * max_label_count
resampled_text = resample(label_text, n_samples=max_label_count, random_state=0)
output_text = output_text + resampled_text
output_labels = output_labels + resampled_labels
return output_text, output_labels
clf = Pipeline(
steps=(('tfidf_vectorizer', TfidfVectorizer(stop_words='english')),
('clf', RandomForestClassifier(n_estimators=250, n_jobs=-1)))
)
resampled_data, resampled_labels = upsample(data, labels) # UPDATE: produces ~700,000 samples, which many duplicates
labels = label_encoder.fit_transform(labels)
X_train, X_test, y_train, y_test = train_test_split(data, labels, test_size=0.5, random_state=0) # UPDATE: many duplicates in both training and test data sets as a result of upsampling
clf.fit(X_train, y_train)
test_score = clf.score(X_test, y_test)
logger.debug('Test Score: %s', test_score) # 0.98-0.99%
cross_validation_results = cross_val_score(clf, data, labels)
logger.debug('Cross Validation results: %r', cross_validation_results) # [98.7, 99.1, 97.8]
y_test_predicted = clf.predict(X_test)
output_classification_report = classification_report(y_test, y_test_predicted, target_names=label_encoder.classes_)
logger.debug(output_classification_report) # 0.95-1.0 for precision and recall for all classes
clf_file_name = os.path.join(directory, clf_name)
joblib.dump(clf, clf_file_name)
label_encoder_file_name = os.path.join(directory, label_encoder_name)
joblib.dump(label_encoder, label_encoder_file_name)
# Later, in a different script
clf_file_name = os.path.join(directory, name)
clf = joblib.load(clf_file_name)
label_encoder_file_name = os.path.join(directory, name)
label_encoder = joblib.load(label_encoder_file_name)
predictions = clf.predict(new_data)
logger.debug(clf.score(new_labels, predictions)) # 50-70%
此外，当我使用new_data重新训练分类器并在new_data上进行预测时，它是100％准确的。我知道它会得到更高的分数，因为它已经看到了这个例子，但我一直在阅读随机森林中的袋外错误，我理解这可能是我的问题，但我不熟悉OOB知道如何纠正这个。我不知道怎么从这里开始。我该如何解决这个问题？
在发布我自己的问题之前，我已经阅读了以下问题/资源来解决我的问题，但如果我忽略了他们的某些内容，请随时告诉我：